[TASK] Proper template for EXT:cshmanual

Use the proper template mechanism and a toolbar for the cshmanual ext to
let it look like all other backend modules.

Change-Id: I6b1a4cfe036034d09caa71a8914eed359f2da930
Resolves: #54184
Releases: 6.2
Reviewed-on: https://review.typo3.org/25933
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer