DOC-2363 TinyMCE 7.1 Release notes & community changelog

[FarzadHayat]

Ticket: DOC-2363

Site: 7.1 Release Notes
Site: 7.1 Changelog

Changes:

• Add 7.1 staging template to staging/docs-7 for Community and GA Docs Release.

Pre-checks:

• Branch prefixed with feature/7/ or hotfix/7/
• modules/ROOT/nav.adoc has been updated (if applicable)
• Files has been included where required (if applicable)
• Files removed have been deleted, not just excluded from the build (if applicable)
• Files added for New product features, and included a release note entry.
• Bump api-version to 7.1
• Update supported-versions.adoc with TinyMCE 7.1 row
• Add/remove dummy cell in release-notes.adoc if necessary

Review:

• Documentation Team Lead has reviewed

[FarzadHayat]

Re-opened PR with corrected branch name #3205