[FEATURE] Make select static country configurable to
 only show given countries
Add email confirmation in edit controller
Add missing templates and rename where method was
 renamed
Improve documentation
Fix extbase type for usergroups
Cleanup typoscript parameters

Resolves: #49875, #28010, #27932
Releases: 6.0
Change-Id: I53a5ac11590b8a67814f2f26aa3c414757117785
Reviewed-on: https://review.typo3.org/22196
Reviewed-by: Sebastian Fischer
Tested-by: Sebastian Fischer
Reviewed-on: https://review.typo3.org/24554