Add maintainer oriented documentation with guidelines and expectations for "good first issue" and "help wanted" issues

[sarayourfriend]

Problem

#2155 identifies new guidelines and expectations we should follow for issues labelled "good first issue" or "help wanted". We need to codify these into documentation that can be referenced and shared. Additionally, we should add templates or other tools for maintainers to use that prompt for each piece of information expected to be present on these issues.

Description

Add a new documentation page that describes the guidelines and expectations for issues labelled "good first issue" or "help wanted". Refer to the discussion linked above. The new document created for this issue should be primarily geared towards maintainers and a separate issue will handle updating/adding documentation for new and ongoing contributors.

The document should cover the following:

• Boilerplate text for "how do I get help working on this issue"
• How to identify a "good first issue", "help wanted", no label, and "staff only" issue
• How to pick the technology labels for "good first issue" and "help wanted" issues
• Tips for sufficiently describing the change required to close the issue keeping in mind the label context (good first issue vs help wanted, etc)
  • Include prompts to record or link to Openverse domain-specific documentation if relevant
  • Include prompts to link to relevant pieces of code or related PRs as examples
  • Include prompts to link to external documentation related to the technology labels if appropriate

Note that #2341 will add documentation with a contributor focus, but some of this information may be able to be recorded in a single format approachable for anybody. Feel free to adapt, move or link between these two issues when it makes sense, so long as the context is appropriate.