remove jaeger agent

[frzifus]

Which problem is this PR solving?

Description of the changes

How was this change tested?

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[pavolloffay]

Some use-cases to think about:

• what happens to already injected agents? Does the upgrade of operator updates the agents as well?
• what happens to already created jaeger CRs with agent mode?

[pavolloffay]

The webhook should return an error if agent mode is specified

[pavolloffay]

The agent relevant flags can be removed

Starts a new Jaeger Operator

Usage:
  jaeger-operator start [flags]

Flags:
      --documentation-url string                        The URL for the 'Documentation' menu item (default "https://www.jaegertracing.io/docs/1.56")
      --es-provision string                             Whether to auto-provision an Elasticsearch cluster for suitable Jaeger instances. Possible values: 'yes', 'no', 'auto'. When set to 'auto' and the API name 'logging.openshift.io' is available, auto-provisioning is enabled. (default "auto")
      --health-probe-bind-address string                The address the probe endpoint binds to. (default ":8081")
  -h, --help                                            help for start
      --jaeger-agent-hostport string                    The location for the Jaeger Agent (default "localhost:6831")
      --jaeger-agent-image string                       The Docker image for the Jaeger Agent (default "jaegertracing/jaeger-agent")
      --jaeger-all-in-one-image string                  The Docker image for the Jaeger all-in-one (default "jaegertracing/all-in-one")
      --jaeger-cassandra-schema-image string            The Docker image for the Jaeger Cassandra Schema (default "jaegertracing/jaeger-cassandra-schema")
      --jaeger-collector-image string                   The Docker image for the Jaeger Collector (default "jaegertracing/jaeger-collector")
      --jaeger-es-index-cleaner-image string            The Docker image for the Jaeger Elasticsearch Index Cleaner (default "jaegertracing/jaeger-es-index-cleaner")
      --jaeger-es-rollover-image string                 The Docker image for the Jaeger Elasticsearch Rollover (default "jaegertracing/jaeger-es-rollover")
      --jaeger-ingester-image string                    The Docker image for the Jaeger Ingester (default "jaegertracing/jaeger-ingester")
      --jaeger-query-image string                       The Docker image for the Jaeger Query (default "jaegertracing/jaeger-query")
      --jaeger-spark-dependencies-image string          The Docker image for the Spark Dependencies Job (default "ghcr.io/jaegertracing/spark-dependencies/spark-dependencies")
      --jaeger-version string                           Deprecated: the Jaeger version is now managed entirely by the operator. This option is currently no-op. (default "1.56.0")
      --kafka-provision string                          Whether to auto-provision a Kafka cluster for suitable Jaeger instances. Possible values: 'yes', 'no', 'auto'. When set to 'auto' and the API name 'kafka.strimzi.io' is available, auto-provisioning is enabled. (default "auto")
      --kafka-provisioning-minimal                      (unsupported) Whether to provision Kafka clusters with minimal requirements, suitable for demos and tests.
      --leader-elect                                    Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.
      --log-level string                                The log-level for the operator. Possible values: trace, debug, info, warning, error, fatal, panic (default "info")
      --metrics-host string                             The host to bind the metrics port (default "0.0.0.0")
      --metrics-port int32                              The metrics port (default 8383)
      --openshift-oauth-proxy-image string              The Docker image location definition for the OpenShift OAuth Proxy (default "quay.io/openshift/origin-oauth-proxy:4.12")
      --openshift-oauth-proxy-imagestream-name string   The name for the OpenShift OAuth Proxy imagestream
      --openshift-oauth-proxy-imagestream-ns string     The namespace for the OpenShift OAuth Proxy imagestream
      --platform string                                 The target platform the operator will run. Possible values: 'kubernetes', 'openshift', 'auto-detect' (default "auto-detect")
      --secure-listen-address string                    
      --tls-cipher-suites strings                       Comma-separated list of cipher suites for the server. Values are from tls package constants (https://golang.org/pkg/crypto/tls/#pkg-constants). If omitted, the default Go cipher suites will be used
      --tls-min-version string                          Minimum TLS version supported. Value must match version names from https://golang.org/pkg/crypto/tls/#pkg-constants. (default "VersionTLS12")
      --tracing-enabled                                 Whether the Operator should report its own spans to a Jaeger instance
      --webhook-bind-port int                           The address webhooks expose. (default 9443)

Global Flags:
      --config string   config file (default is $HOME/.jaeger-operator.yaml)

[pavolloffay]

The deployment webhook can be removed as well