LGA-2898: Dockerise cla_frontend

[BenMillar-MOJ]

What does this pull request do?

• Creates run_local.sh for running cla_frontend as a multi-container application with `cla_backend.
• Creates run_local_standalone.sh for running cla_frontend as a standalone container.
• Modifies docker-compose.yaml so it includes cla_backend's docker-compose.yaml
• Adds docker-compose-standalone.yaml which includes a mounted volume between ./cla_frontend and /home/app/cla_frontend in the container.
• Allows changing of the requirements file in the Dockerfile using an environment variable.
• Updates documentation.

Any other changes that would benefit highlighting?

Intentionally left blank.

Checklist

• [x] Provided JIRA ticket number in the title, e.g. "LGA-152: Sample title"

[sonarcloud[bot]]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud