Create Contributing.md

[ArielSAdamsNASA]

Is your feature request related to a problem? Please describe.
Create a Contributing.md file so users know how to engage with cFS.

Describe the solution you'd like
Include instructions on how to report bugs, request a feature, participate in discussions, create pull requests, and view security vulnerabilities.

Additional context
I would like to create a code of conduct for this file. I would also like to explore how cFS could allow more discussions from the community such as using gitter.im, discourse, or a discussions template to use in issues.

Requester Info
Ariel Adams, ASRC Federal

[skliper]

Good plan! There was a draft started as a PR in cFE (I think), and I've sent Gerardo a few things on the PR submission process (and I think he's collected quite a bit of other info). All good stuff to actually formalize and provide to users. Could like to it from the submodules (vs writing one for every repo).

[ArielSAdamsNASA]

@skliper I used the draft from cFE that you mentioned for the cFS contributing.md file, but there are some things missing and topics I would like to add. It would be great to get your feedback! Here is the PR