Document housekeeping tasks before upgrade

Document the housekeeping tasks one should do before an upgrade.

• Introduction
• Run "Fix Karaf" script to delete cache folder (this is more of a post-installation task).
• Do diff on configuration files - only need to migrate config files you have changed
• Dealing with permissions if moving from pre-H29 to post H-29 due to run as non-root user change
• Delete older events

Not every upgrade affects the events table, but include this with caveat that it is an alternate scenario (create separate Jira, if preferred)

• Assess events table size (does this still need to be done?)

• • describe scenario of when to do this, why, and how