Feature: #75691 - Upgrade Analysis - Provide listing of documentation files

See Issue #75691

Description

The install tool now shows all the documentation files that were delivered with the core in the section Upgrade analysis. All files can be read inline, but there is no parsing, plain .rst is shown to the user.

Impact

The install tool features a new main entry point that lists the documentation files shipped with the core. Filtering by tags provided in the documentation files helps to find interesting changes.