RFC: Domain based content dimensions

[Nezaniel (Bernhard Schmitt)]

I’ve split up my considerations into two RFCs:
Configuration

RFC: Fallback graph configuration

##Motivation The current fallback configuration does not cover enough use cases for projects that require content dimensions. It is also rather misleading for both integrators and the service implementations that build up the fallback graphs. Both of this can be improved rather easily. ##Change Log 2017-09-13: Initial reference 2017-09-25: Adjusted naming convention from variant to specialization and extended example to one value having multiple specializations ##Status quo Content Dimensi…

and
Detection

RFC: Detecting Nodes (and trees)

##Motivation We need a new way of detecting the current tree (fka content context) which is more flexible and extensible, e.g. to implement content dimensions based on sub-/top-level-/domains, user groups, the lunar phase etc. ##Status quo Currently, detection of nodes in a specific context is restricted to the request path as it is for all route part handlers. But which tree (fka content context) we’re currently in may be defined by other parameters, which currently are not exposed to the Fr…