[wip] adding compose component to devfile/api

[kernelpanic77]

What does this PR do?:

Changes for including Compose Component to reference a compose yaml file. Generated devworkspace CRDs and schemas for corresponding changes in v1alpha2 api.

I have create an example devfile in samples/devfiles/docker-compose-devfile.yaml

schemaVersion: 2.1.0
metadata:
  name: microservices-demo
attributes:
  controller.devfile.io/storage-type: ephemeral
  controller.devfile.io/scc: container-build
components:
  - name: frontend-dev
    docker-compose:
      uri: ./utils/docker-compose.yml
commands:
  - id: init-project
    exec:
      component: frontend
      commandLine: yarn install
      workingDir: $PROJECT_SOURCE
events:
  postStart:
    - init-project

⚠️ Do not merge this PR yet.

Which issue(s) this PR fixes:

#501

PR acceptance criteria:

Testing and documentation do not need to be complete in order for this PR to be approved. We just need to ensure tracking issues are opened.

• Open new test/doc issues under the devfile/api repo
• Check each criteria if:
• There is a separate tracking issue. Add the issue link under the criteria
  or
• test/doc updates are made as part of this PR
• If unchecked, explain why it's not needed

• Unit/Functional tests

• QE Integration test

• Documentation

• Client Impact

How to test changes / Special notes to the reviewer:

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: kernelpanic77

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[l0rd]

I have provided some suggestions. Those should be applied to v1alpha1 too.

[l0rd]

Trying to address the points raised (rightfully) by @amisevsk

Suggested change

	// Allows importing into the devworkspace docker-compose files
	// defined in a given manifest. For example this allows the reuse of previously
	// docker-compose files used to define configuration for managing
	// multiple containers at the same time.
	// Allows referencing an existing Compose files so that its abstractions as
	// Services and Volumes will be included in the resulting development
	// environment.

[kadel]

Can we please pause and think about how this is actually going to work? Please see and continue discussion at #501 (comment)