TYPO3 Core

The Frontend Request Workflow has seen drastic separation
due to the introduction of PSR-15 (Middleware concept) and
the Context API in TYPO3 v9.

For TYPO3 v10, this now allows to further refactorings
to reduce dependencies to TSFE, allowing to run various
parts of TYPO3 Frontend without having a global TSFE object
in place.

The goal is to set up:
- Site + Language
- Redirects
- Page ID Resolving
- Page Argument Validation (cHash)
- Frontend + Backend User Authentication

before any TSFE dependency is in place.

Further refactorings can then happen as TSFE is scoped
more into parts of TYPO3.