Remove server side rendering functionalities

[Kaliumhexacyanoferrat]

As a developer of web applications, I would like to use JS based frontend technologies for UI (via SPAs) as well as a simple backend layer, so that I can quickly create feature rich apps.

Currently, the GenHTTP server framework features a path for server-side rendering of websites. This functionality creates some complexity within the server code (e.g. GetContent() and loads of routing logic) but is merely used.

Therefore, all capabilities for server-side rendering are now considered deprecated and will be removed with version 9 released together with .NET 9 end of 2024.

This will allow future development to focus on much-needed features such as OpenAPI integration or JWT authentication.

This change induces the removal of the following modules:

• Authentication.Web
• AutoReload
• Pages
• Razor, Scriban, Markdown
• Robots
• Minification
• Sitemaps
• Websites
• All of the GenHTTP.Themes

The changes will be done in an additional branch to allow features to be added to master as long as possible.

Steps and roadmap

• Update the readme, nuget packages, templates, themes and website to reflect the deprecated state
• Create the new branch and remove the functionality
• Create new documentation branches having the old functionality already removed from the website
• Merge the removal into master
• Release the changes alongside .NET 9 support