Update documentation

[TAnas0]

What is the Purpose?

Update our basic documentation in the repository.
The README is a bit overwhelming and too specific. It also tries to describe all possible scenarios for running Activity:

• Using pipenv or virtualenv
• Operating System specific extra information
• Setup of databases and managing them

I'd rather have a friendlier README with a quick Getting Started section based on Docker and Docker Compose, and leave the rest to the user who is doing the setup, and knows their machine.

What was the approach?

Briefly describe the approach used to address the issue

Are there any concerns to addressed further before or after merging this PR?

None

Mentions?

@andrew @ninetteadhikari

Issue(s) affected?

Fix #758

[codecov]

Codecov Report

Merging #760 (5085932) into develop (baa15a0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #760   +/-   ##
========================================
  Coverage    57.61%   57.61%           
========================================
  Files          143      143           
  Lines         9223     9223           
========================================
  Hits          5314     5314           
  Misses        3909     3909           

[andrewtpham]

Looks good, thanks for all this clean up work 💪 @TAnas0