Import KCM documentation from plasma-desktop.git.

This moves the handbooks for the KCMs migrated into kio.git in
367a56b5 and 335f570f from plasma-desktop.git to here.

The 'ebrowsing' handbook has been renamed to 'webshortcuts' to
match what the KCM actually requests.

Branched from plasma-desktop.git, master branch, at commit
2d7fca61f57082bb96d48b92df16871ad7b0a271

Change-Id: I72e7026f3d818c71077ca81fdb6b4491173da2c0
CCMAIL:kde-i18n-doc@kde.org