EQS-487: Add Cloud Build configuration for linting and rename existing YAML files

[VirajP1002]

Motivation and Context

This PR involves updating the current pipelines to adopt appropriate naming conventions and adding in a Cloud Build configuration for linting (and testing which will be added in the future).

Note: We may need to discuss the possibility of using a prebuilt image for Megalinter as this will make linting a quicker task as an image needs to be retrieved to run Megalinter via Docker. Moreover, this could have an impact on the time the trigger runs for when testing is added.

What has changed

As a result, we needed to update the names for the Cloud Build YAML files which will be used in the Cloud Build triggers and we added in the Cloud Build configuration to support linting using Megalinter.

How to test?

• Check the new linting configuration is correct and the new names are appropriate
• After creating a dev environment using the changes in the cir-migration-terraform repo, run all 3 triggers against this branch:
  • cir-proxy-service-lint-and-test
  • cir-proxy-service-build-push-deploy
  • cir-proxy-service-build-on-pr

Note: Expect linting to fail until the PR to upgrade fastAPI and Starlette has been merged

[petechd]

We need to add the "test" part here too?

[petechd]

We need to add a link to the new MegaLinter dependency/call in the "CIMS Proxy Service - GitHub Repository" doc in "CIR Migration Service" directory. And poetry if we add testing.