Add docker

[tmpayton]

Summary (required)

• Resolves Add Docker #6075

This PR adds Docker for local laptop development.

Summary of Changes:

1. Updated Readme with setup instructions
2. Adds .dockerignore, dockerfile, and docker-compose files to run Docker
3. Modified advisory_opinions.py, archived_murs.py, and current_cases.py to remove circular imports that were causing an error
4. Added other connection strings for the local database, elasticsearch, and redis that work with docker while preserving previous laptop setup settings

Required reviewers 2 - 3 developers

Impacted areas of the application

General components of the application that this PR will affect:

• readme
• legal docs
• laptop setup

How to test

1. Download Docker Desktop
2. Follow this wiki to test setup, pytest, and locust https://github.com/fecgov/openFEC/wiki/Docker-Setup-for-Local-Development
3. Follow this wiki to test elasticsearch: https://github.com/fecgov/openFEC/wiki/Docker-Setup-and-Test-Elasticsearch-Locally
4. Follow this wiki to test redis and celery: https://github.com/fecgov/openFEC/wiki/Docker-Setup-and-Test-Redis-and-Celery-Locally

[codecov]

Codecov Report

Attention: Patch coverage is 72.72727% with 3 lines in your changes missing coverage. Please review.

Project coverage is 88.42%. Comparing base (02b2fbd) to head (a314568).
Report is 5 commits behind head on develop.

Files with missing lines	Patch %	Lines
webservices/rest.py	33.33%	2 Missing ⚠️
webservices/tasks/__init__.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6093      +/-   ##
===========================================
- Coverage    88.46%   88.42%   -0.04%     
===========================================
  Files           82       82              
  Lines         9091     9098       +7     
===========================================
+ Hits          8042     8045       +3     
- Misses        1049     1053       +4     

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