feat: implement initial version of kyma agent

[muralov]

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Description

Changes proposed in this pull request:

• Implements basic functionality of Kyma agent
• Implements integration tests
• Implements unti tests
• Implements basic retriever

Related issue(s)

214

[github-actions[bot]]

Note(s) for PR Auther:

• The integration test will be skipped for the PR. You can trigger it manually after adding the label: run-integration-test.
• The evaluation test will be skipped for the PR. You can trigger it manually after adding the label: evaluation requested.
• If any changes are made to the evaluation tests data, make sure that the integration tests are working as expected.
• If any changes are made to how to run the unit tests, make sure to update the steps for unit-tests in the create-release.yml workflow as well.

  Note(s) for PR Reviewer(s):

• Make sure that the integration and evaluation tests are working as expected.