added guides to conduct and contributing

[shimwell]

Proposed changes

This is long overdue, this PR includes a contribution guide and standard code of conduct.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code refactoring
• Documentation Update (if none of the other choices apply)
• New tests

[codecov]

Codecov Report

Merging #123 (96fbf9f) into develop (b43d58b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #123   +/-   ##
========================================
  Coverage    97.56%   97.56%           
========================================
  Files           76       76           
  Lines         4717     4717           
========================================
  Hits          4602     4602           
  Misses         115      115           

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[shimwell]

@RemDelaporteMathurin perhaps this helps with that document you are writing