feat: Add a new Triage Onboarding issue type

[bmtcril]

• Adds a new "GitHub Request - Triage Onboarding" issue template per [GH Request] Update onboarding templates #1527
• Updates the current "GitHub Request - Onboarding" to "GitHub Request - Core Contributor Onboarding" since I believe there is no longer any other kind of GitHub onboarding?
• Update the names of other issue templates to preserve ordering

[kdmccormick]

Thanks! Triage Onboarding looks great. I think we could drop the Squad, Start Date, User Squad, and maybe even Urgency fields? It could also be good to add a field asking for their CC nomination thread, as that would tell us all the types of access they need.

[bmtcril]

Thanks, I've dropped the Squad, Start Data, and Urgency fields since Squad can be handled in the special requests section. All other request types have Urgency, so I'm not sure how people will feel about dropping that, but it is both kind of implicit in the type of request and there is a safety valve in the special requests section if need be. There was already a CC Thread field.

[kdmccormick]

Sounds good w.r.t. Urgency. Looks like Squad is still there, though?

I would also recommend adding a Special Requests section to the Triage onboarding as well so that triage folks can ask to be on additional read-only teams.

[kdmccormick]

Thanks! 🚀

[sarina]

I would add validations: required: true to this since now this is a CC Onboarding specific template.