jimfuqian/BB2 Recover Dockerfile.selenium-jenkins-python311-plus-chromedriver (for building CI docker iamge) and clean up unused

[JFU-NAVA-PBC]

JIRA Ticket:
BB2-XXXX

What Does This PR Do?

For unknown reason, the docker file for building CI docker image (currently at AWS ECR: public.ecr.aws/f5g8o1y9/bb2-cbc-build-selenium-python311-chromium:latest ) become empty and removed by later PR, this PR restore that dockerfile and cleanup other unused to avoid confusion, also updated the readme to document the current manual process of building and pushing the image.

What Should Reviewers Watch For?

If you're reviewing this PR, please check for these things in particular:

Validation

One way to verify is to go to Jenkins jobs and trigger a CI check with selenium tests
I did one already as shown:

What Security Implications Does This PR Have?

Please indicate if this PR does any of the following:

• Adds any new software dependencies
• Modifies any security controls
• Adds new transmission or storage of data
• Any other changes that could possibly affect security?

• Yes, one or more of the above security implications apply. This PR must not be merged without the ISSO or team
  security engineer's approval.

Any Migrations?

• Yes, there are migrations
  • The migrations should be run PRIOR to the code being deployed
  • The migrations should be run AFTER the code is deployed
  • There is a more complicated migration plan (downtime,
    etc)
• No migrations

[sb-benohe]

Thanks for cleaning this up!