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 #2061977 by InternetDevels, kim.pepper, ianthomas_uk, herom, rhm50, naveenvalecha, andypost,  mandar.harkare, sergeypavlenko, sidharthap, SIz, tkuldeep17: Replace user_access() calls with ->hasPermission() in all core modules except user.

Revert "Issue #2061977 by InternetDevels, kim.pepper, ianthomas_uk, herom: Replace user_access() calls with ->hasPermission() in all core modules except user."

Fixing commit credit.

This reverts commit 25afa810.

Issue #2061977 by InternetDevels, kim.pepper, ianthomas_uk, herom: Replace user_access() calls with ->hasPermission() in all core modules except user.

Issue #2002650 by mrsinguyen, chertzog, legolasbo, Erik Erskine, rhm50, sandergo90, grisendo, targoo, janstoeckler, maximpodorov, beowulf1416: Improve maintainability by removing unused local variables.

Issue #1872876 by chx, fubhy, dawehner, alexpott, tim.plunkett: Turn role permission assignments into configuration.