[#58387050] Initial commit of Couchsurfing-related checklist info.

Will need to review this again against some of the other resources that are publicly available.
Update checklist.md

Updates for today. Will return to this tomorrow morning.
Update README.md
Update README.md
Update checklist.md

Commit for safekeeping - final edits pending.
Update checklist.md
Update checklist.md
Update checklist.md

Final changes.
Update checklist.md

Added updates based on suggestions from Alex (prior to merge).
Merge pull request #1 from Couchsurfing/gb-ios-app-release-checklist-58387050

Gb ios app release checklist 58387050