Seperate navigation tree cache for each host (Case 166581)

[MalteWunsch]

This allows us to populate navigation trees on dedicated preview servers with host names like "preview.webfactory.de" under different visibility rules.

Technically speaking, at least two issues could be considered as BC breaks:

• the changed location of the tree cache file
• the changed constructor parameters of TreeFactory

But I'd like to argue that for practical reasons, both of them should be consivered as internal implementation details. The TreeFactory class/service was never intended to be overwritten, as suggested by the private properties ranging back to 2017. => I would tag a release as a minor version.

[MalteWunsch]

@mpdude Seems to work as intented and I don't know which ghost I was hunting yesterday.

Fabian and I like this approach because it is encapsulated inside the bundle without a BC (arguably 👆).

With the alternative "only one tree cache with modified PageBuildDirector or an additional BuildDirector", we would need to consider the different tree structure in the blocks in src/Resources/views/Navigation/navigationBlocks.html.twig (or the overriding Twig template in the project respectively).

A downside of this approach is that in edge cases with projects with multiple host names (e.g. www.youthpass.eu and demo.youthpass.eu) the tree is cached once per host name - but this seems to be negigible (e.g. for GBA, the tree cache is ~220 kb).

[mpdude]

In the project where we actually implemented the "preview" solution, we chose to use different Kernel instances for different modes of operation – as suggested in https://symfony.com/doc/current/configuration/multiple_kernels.html.

That gives complete separation of all types of caches, including the HTTP level, navigation tree, routing etc. So, I think this PR should be closed.