Contribution guide consolidation

[kattni]

• Creates customisable versions of code and docs contribution guides
  • Requires changes to config.yml to use in a target repo.
• Adds a customisable feature request explanation guide
• Updates docs-tools testbed to include the guides.
• Cleans up code and docs guides.

Closes beeware/beeware#24

TODO:

• Check entire PR for TODO, and resolve.

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[kattni]

I'm not adding TODO to the spelling word list, so the builds will fail until you complete the TODOs in the feature request guide.

[freakboy3742]

I've just pushed updates from a review of the new content; this is looking really good.

For the benefit of other observers - Kattni and I have spoken in person about some next steps, including some additional re-organization of this content prior to integrating into Toga, Rubicon and Briefcase.

[kattni]

@freakboy3742 The following pages are ready for an initial review.

• First-time contributors: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/first_time_contributors/
• Reproduce an issue: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/issue_reproduce/
• Release process: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/release_process/
• Proposing a new feature: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/feature_proposal/
• Feature proposal process: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/feature_proposal_process/

[kattni]

Round two ready for initial review:

• Write documentation: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/docs_process/
• Setting up a development environment: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/dev_environment/
• Writing, running, and testing code: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/code_run_test/
• Building documentation: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/docs_build/
• Writing documentation: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/docs_contribute/
• Code style guide: https://beeware-docs-tools--94.org.readthedocs.build/en/94/content_test_bed/how-to/contribute/code_style_guide/