Backport Jira Cloud and Server integration fixes

We have following 2 issues related to Jira Cloud and Server integration:

• Jira Integration: Deprecated API Returning 410 ... (#569792 - closed) • Anton Smith • 18.5
• Jira Server/Data Center: Viewing issues broken ... (#575803 - closed) • Anton Smith • 18.6

@anton helped with implementation of the fixes in following 2 MRs, which we need to backport to maintainer versions. Given when the fixes were implemented we need to backport as follows:

• Update Jira integration to use token-based pagi... (!206815 - merged) • Anton Smith • 18.5
  • 18.4, 18.3
• Support Jira Cloud and Server issue fetching (!208859 - merged) • Anton Smith • 18.6
  • 18.5, 18.4, 18.3

Backporting

• Documentation for backporting to maintainer versions
• Backporting announcement with details for reference
• References to backport requests & customer interest
  • #569792 (comment 2857701155)
  • #569792 (comment 2794474281)
  • #569792 (comment 2768164197)