Upgrade story for SaaS Accelerator

[santhoshb-msft]

Is your feature request related to a problem? Please describe.
ISV has the ability to upgrade the Saas Accelerator

Describe the solution you'd like

1. Documentation on the upgrade from version to version @santhoshb-msft
2. Upgrade script with Private endpoint. [This is dependent on the PE] @msalemcode
3. Upgrade script testing with Multiple AppId. @neelavarshad
4. Add the release version on the pages and display a message if there is a new version @santhoshb-msft

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
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[santhoshb-msft]

Current status 8/15
-1 pending
-2 fixed
-3 needs testing after the release of 8
-4 fixed

[santhoshbomma9]

@fthorntonai - can you please install the current 7.6.2 and use our upgrade script to upgrade to main and list out the challenges please?