[Ranking criteria] Add metadata draft

[Okorin]

Summary

• While a relatively small sample size, i'll try going with separate articles for drafts where appropriate (we also talked about this in the latest NAT meeting). Forum conversation and poll in : https://osu.ppy.sh/community/forums/topics/1931114?n=1
  • Had to rearrange the main RC article, took some creative liberty:
    • The info included is still the same, only mentions to other general rules as being part of the beatmap modding process (like VCC or content usage permissions) were added
    • metadata is added as its own article with a reference in the table of contents
      since the changes aren't intended to change ANY behaviour and are instead about formatting, I skipped making a separate discussion thread for moving this around
• Adds draft from https://osu.ppy.sh/community/forums/topics/1894663?n=1 as its own article

The comment about (Slowed Down Ver.) is not included in this draft for now for the following reason: These songs aren't common enough to warrant their own mention and they'd be covered by "make a sensible marker" via the #### Ver. guideline introduced.

Some american english may still be left and some phrasing may still include a bit simpler language. I personally think the simpler language is fine

[osu-wiki-observatory]

Someone else has edited same files as you did. Please check their changes in case they conflict with yours:

• Update Ranking Criteria to allow red lines to be used for out-of-range slider speeds #10872, files:
  • wiki/Ranking_criteria/en.md

[Okorin]

@peppy You asked me to ping you on the conversation to check this out