New dev containers for testing e2e tests and building java code

[srbarrios]

What does this PR change?

This PR aims to provide two different devcontainers.
One for testing purposes, acting as a controller vm.
The other for building java code.

Notice that for .devcontainer/test/id_rsa_test_env we already have a similar commit here testsuite/features/upload_files/ssh_keypair, so it should be fine.

GUI diff

No difference.

• DONE

Documentation

• No documentation needed

• DONE

Test coverage

• No tests

• DONE

Links

Ports:

• Manager-4.3

• DONE

Changelogs

Make sure the changelogs entries you are adding are compliant with https://github.com/uyuni-project/uyuni/wiki/Contributing#changelogs and https://github.com/uyuni-project/uyuni/wiki/Contributing#uyuni-projectuyuni-repository

If you don't need a changelog check, please mark this checkbox:

• No changelog needed

If you uncheck the checkbox after the PR is created, you will need to re-run changelog_test (see below)

Re-run a test

If you need to re-run a test, please mark the related checkbox, it will be unchecked automatically once it has re-run:

• Re-run test "changelog_test"
• Re-run test "backend_unittests_pgsql"
• Re-run test "java_pgsql_tests"
• Re-run test "schema_migration_test_pgsql"
• Re-run test "susemanager_unittests"
• Re-run test "javascript_lint"
• Re-run test "spacecmd_unittests"

Before you merge

Check How to branch and merge properly!

[srbarrios]

@renner @mbussolotto @uyuni-project/qe
This works, and this is completely isolated from any other code in the repository, so let me know you if you agree on merging this please.