Improve Compatibility documentation

[PProfizi]

• The compatibility table should be at the start of the "Getting Started" page
• It mentions having to synchronize the ansys.grpc.dpf module but not explicitly the server and python client compatibility
• The "Architecture" section mentions Ansys 2021R2 as required while the "Installation with PIP" section mentions "Ansys 2021 R1 or later" and gives only the command pip install ansys-dpf-core which is wrong is using Ansys 2021R1 (should be pip install ansys-dpf-core<0.3.0)
• We might actually want to mention compatibility in the ReadMe, along with specifying that the installation command is for Ansys 2021 R2 onward.
• We can also customize the Issue template to add a tick box with "I made sure I am following the Compatibility guidelines", with an hyperlink to the doc.
• The Ansys 2021R1 row of the table should be visually separated in some way (thicker boundaries?) --> Could not find how to do this

[codecov]

Codecov Report

Merging #256 (8bb33d1) into master (8dafee0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #256   +/-   ##
=======================================
  Coverage   85.77%   85.77%           
=======================================
  Files          52       52           
  Lines        5702     5702           
=======================================
  Hits         4891     4891           
  Misses        811      811           

[cbellot000]

@PProfizi I don't think that the docker page is up to date, we should not add links to it until it is, what do you think?

[PProfizi]

@cbellot000 agreed.