Issue #2286971 by znerol, Berdir, almaudoh, cilefen: Remove dependency of current_user on request and authentication manager

Issue #2229145 by znerol, neclimdul, larowlan, alexpott, joelpittet, almaudoh, tadityar: Register symfony session components in the DIC and inject the session service into the request object

Revert "Issue #2229145 by znerol, neclimdul, larowlan, joelpittet, almaudoh: Register symfony session components in the DIC and inject the session service into the request object"

This reverts commit b926f5d8.

Issue #2229145 by znerol, neclimdul, larowlan, joelpittet, almaudoh: Register symfony session components in the DIC and inject the session service into the request object

Issue #2348679 by znerol, Wim Leers: Move the remaining procedural page cache code to the page cache stack middleware

Issue #2303673 by dawehner, damiankloip, effulgentsia, Fabianx: Implement stackphp; cleanup handlePageCache() and preHandle()