Issue #2795539 by Shashwat Purav, shashikant_chauhan: Punctuation issue for Place block module in hook_help

(cherry picked from commit a491c499)

Issue #2739079 by DyanneNova, akalata, webchick, tkoleary, pwolanin, SKAUGHT, elliotc, lizzjoy, YesCT, yoroy, miwayha: Create a validated design for Block Place module

Issue #2791335 by pwolanin: Optimize repeated method call in  PlaceBlockPageVariant::build, use service instead of direct query string

(cherry picked from commit 2acb2aa0)

(cherry picked from commit e51f98e1)

Issue #2724819 by SKAUGHT, pwolanin, tim.plunkett, tkoleary, tedbow, webchick, yoroy, Wim Leers, brantwynn, Bojhan: Create experimental module for place block on any page feature