Feature: #58366 - Add "auto" Option for config.absRefPrefix

See forge#58366

Description

The TypoScript setting config.absRefPrefix can be used to allow URL rewriting like giving a hard prefix for all relative paths. As an alternative to config.baseURL to be set to a specific domain absRefPrefix can autodetect the site root and use that instead of manually setting this option.

Frontend:

The new option can be set like this:

config.absRefPrefix = auto

instead of hardcoded values for different environments or when moving installations in subfolders.

[ApplicationContext = Production]
config.absRefPrefix = /

[ApplicationContext = Testing]
config.absRefPrefix = /my_site_root/

As the feature only works with path prefixes, and not with host name variables from the server, the new option is also safe for multi-domain environments to avoid duplicate caching mechanism.

Impact

The new special option can be used to automatically set up installations and distributions like the Introduction Package where a site configuration is shipped with the system but might need to be adjusted.