Refactor the Windows installer to allow for branding and customisations

The Windows installers code should allow for full branding and customisation by third-parties so that the code can be reused in other circumstances. By default, the installers will be branded for installing Adoptium Temurin and coded to install the binaries produced by the project; however, there is value in reusing common behavior and logic across participants who are installing Temurin as a different branded binary, or even a different custom build.

The customisation code should not be stored in the Adoptium repository for users other than Temurin. At the moment [there are customisations](https://github.com/adoptium/installer/tree/master/linux/jdk/debian/src/main/packaging) that require developers to update the Adoptium installer repository for their own use - this should not be necessary.

This issue is to capture requirements for the refactoring of the existing code to permit current external requirements, and ensure that those currently using the code can include their requirements, and track any changes undertaken.

(Raising on behalf of @karianna . Please amend or update as required.)

Start by reviewing the existing Windows installer code and the customisations referenced in linux/jdk/debian/src/main/packaging. Compare the current branding and binary assumptions with the external reuse requirements; done means the requirements and affected changes are clearly tracked for current users and third-party custom builds.

Written by the indexing model from the issue text.