Codify new expansion release schedule

[pkmnsnfrn]

Description

Add a document detailing the proposed expansion release schedule and process around Big Features

People who collaborated with me in this PR

@Pawkkie

Discord contact info

pkmnsnfrn

[Pawkkie]

Putting feedback here rather than discord, I think the doc itself is great as I've said there:

• Would suggest putting it in docs/team_procedures, and also moving scope.md to that folder. I think it makes sense to have all our developer-facing docs in one place. Perhaps that's not suitable though, feel free to ignore
• Should add to the website via SUMMARY.md as per Added scope document and made changes to pull request template #5706

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Do we think it's better if I don't approve this given that I helped write some of it, or am I fine to do so given that it's been met with approval from the problem squad (assuming the latter but want to clarify with a second opinion first)

[pkmnsnfrn]

• Would suggest putting it in docs/team_procedures, and also moving scope.md to that folder. I think it makes sense to have all our developer-facing docs in one place. Perhaps that's not suitable though, feel free to ignore

Done

• Should add to the website via SUMMARY.md as per Added scope document and made changes to pull request template #5706

Done

Do we think it's better if I don't approve this given that I helped write some of it, or am I fine to do so given that it's been met with approval from the problem squad (assuming the latter but want to clarify with a second opinion first)

I think you should not approve but don't feel strongly

[AsparagusEduardo]

Scope's directory should also be updated

Suggested change

	<!--- If you believe this PR qualifies as a "Big Feature" as defined in docs/schedule.md, please let a Maintainer know! -->
	<!--- If you believe this PR qualifies as a "Big Feature" as defined in docs/team_procedures/schedule.md, please let a Maintainer know! -->

[AsparagusEduardo]

You still need to update the scope document URL

Missing the other part of the review