Issue #2432837 by Wim Leers, Fabianx: Make cache contexts hierarchical (e.g. 'user' is more specific than 'user.roles')

Issue #2445743 by dawehner, Wim Leers: Allow views base tables and entity types to define additional cache contexts

Revert "Issue #2445743 by dawehner, Wim Leers: Allow views base tables and entity types to define additional cache contexts"

This reverts commit a87aff86.

Issue #2445743 by dawehner, Wim Leers: Allow views base tables and entity types to define additional cache contexts

Issue #2322233 by Temoor, Mirroar, estoyausente: Replace all instances of user_role_load(), entity_load('user_role') and entity_load_multiple('user_role') with static method calls.

Issue #2340123 by Wim Leers: Setting cache tags can be tricky: use strings instead of nested arrays to improve DX.

Issue #2273277 by Wim Leers, effulgentsia, Fabianx: Fixed Figure out a solution for the problematic interaction between the render system and the theme system when using #pre_render.

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #2099131 by jessebeach, Wim Leers, catch, Berdir, benjifisher, martin107, andypost: Use #pre_render pattern for entity render caching.

Issue #2188565 by Wim Leers, Berdir: Test coverage for Comment, Custom Block, Node, Taxonomy Term and User entity cache tags.