Update 4.3.7 Docs Removing the 3.X --> 3.5 upgrade step

e*Overview:*

1. Remove the need to upgrade to 3.5 when coming from 3.4 or earlier.
https://confluence.atlassian.com/display/DOC/Upgrading+Confluence+Manually

2. Reinforce the concept that "Upgrades between major versions only are necessary" (like in JIRA)
2.X --> 3.X --> 4.3.7 --> 5.0

Detailed tasks:

• DONE: Fix the mentions of 3.5 on this page:
  https://confluence.atlassian.com/display/DOC/Upgrading+Confluence
  DRAFT: https://confluence.atlassian.com/display/DOC/DRAFT437+-+Upgrading+Confluence

• DONE: Update this page:
  https://confluence.atlassian.com/display/DOC/Upgrading+Confluence+Manually
  DRAFT: https://confluence.atlassian.com/display/DOC/DRAFT437+-+Upgrading+Confluence+Manually

• DONE: Discuss with Renan: What if the customer wants to upgrade from 3.4 to 4.0, or from 3.4 to 4.2 – is that a likely scenario e.g. because of license allowances, and should we add a note saying that they must then go via 3.5? Answer: Does not apply.

• DONE: Update the 4.3 upgrade notes
  https://confluence.atlassian.com/display/DOC/Confluence+4.3+Upgrade+Notes
  DRAFT: https://confluence.atlassian.com/display/DOC/DRAFT437+-+Confluence+4.3+Upgrade+Notes

• DONE: Update the 5.0 upgrade notes
  https://confluence.atlassian.com/display/DOC/Confluence+5.0+Upgrade+Notes

• DONE: Change the Bamboo job that generates the upgrade notes – talk to Steve L:
  • Remove the 3.5 step: "If your version of Confluence is earlier than 3.5.x, then you should upgrade to Confluence 3.5.x before upgrading to Confluence 4.3.x."
  • Fix the link on "release notes and upgrade guides" while we're at it.

• DONE: Check the 4.3.7 issues for other items that require docs.
  Tues 29/1: Checked – all bug fixes; no docs required.

• TO DO AT LAUNCH: Publish the updated pages

• TO DO AT LAUNCH: Make sure the Confluence 4.3.7 upgrade notes do not include the 3.5 step