Add Contributing File

[bytecauldron]

It can be loosely based on the official Awesome file: https://github.com/sindresorhus/awesome/blob/main/contributing.md

[bytecauldron]

Some ideas to specify when creating new issues or pull requests. Some of this might be subject to change when I close this issue out.

• Content should to be related to GMS2.3+ in a reasonable way. I.E. compatible libraries, guides, etc. I'm trying to avoid GMS1 content but it could be added if it's compatible with GMS2.3+
• Issues can be created for spelling errors, pruning dead links, or specifying an asset is now free or became commercial. Additionally authors can ask for the removal of their content, if requested.
• Suggestions for new categories, new links, more detailed descriptions is highly encouraged and should be submitted as issues.
• I feel merging forks would be fine if it adds a ton of new resources and they have been organized similarly to the existing list, but I dunno. Just spitballing.

[bytecauldron]

Contributing file was created with the suggested guidelines.