chore: refactor docker images

[techfg]

What does this PR do?

Refactor docker image creation, tagging, etc.

1. Images tagged to ECR with "FULLSHA.." to ensure unique pointer to image
2. Images tagged to ECR with "FULLSHA-latest" which corresponds to the above - This ensures the "Release" job can find the "latest" for a given SHA. This is not an ideal solution but same approach (just more reliable) as previous. The Release job/process needs to be revisited/improved in general.
3. Ensures latest code (all modules) is built & used whenever running in docker in local dev - Accomplished by having npm run in-docker point to nx run platform:serve-image for dev
4. Introduces a "BUILD_VERSION" for platform (used to be GITSHA) that contains a fully versioned value to ensure uniqueness
5. Always build new image in dev & test runs locally eliminating the check for whether or not an image already exists for the current SHA. This had several shortcomings including not guaranteeing that the latest code (e.g., uncommitted changes) was being tested.
6. Always use current time for "versioned" assets in platform to ensure they are force fetched

Testing

All tests pass locally, running platform via npx run start and npm run in-docker all works and tests pass against both. ci & e2e tests will cover rest.