Issue #3204810 by andypost, RoSk0, smustgrave, quietone, cedewey, Amber Himes Matz, larowlan, benjifisher: Add new permission for accessing help pages

Issue #3087499 by andypost, smustgrave, Amber Himes Matz: Merge Help Topics classes into Help with BC layer

Issue #2095121 by clemens.tolboom, jibran: Ensure every path in routing.yml files has a leading slash.

Issue #2051097 by dawehner, Manuel Garcia, tlattimore, neclimdul: Change 'pattern' to 'path' in *.routing.yml files.

Issue #1981368 by tim.plunkett, Crell, webchick: Convert all routes to 'module_name().foo_bar()' naming convention.