Two small security hardenings for our IE users and those with Adobe products. Aligns it more with https://github.com/twitter/secureheaders#secureheaders---

fix identation in public/irequest.php

Replace deprecated function calls to SecureRandom

Remove unused deprecated function from l10n.php

Revert "Remove unneeded check if htaccess test file already exists"

fix principal constructor for dav

Fix OAuth external storage auth for step 2

improve personal page template

remove unneeded 'goto' prefix from settings anchors

webDAV select bug fixed

Stricter autoloader

Assume apps from the appstore are compatible with the current version

Do not increase filecount in web on file update

Remove generateRandomBytes from OC_Util

remove extra slogan footer from Personal and Admin pages

Filtering is done server-side already so only compatible apps are delivered. Otherwise this leads to a ton of error messages as the info.xml cannot be read at that state.

Fixes https://github.com/owncloud/core/issues/21556

Concat also the other results

Otherwise this will ignore the two last checks 

Remove code related to session regeneration after some time

I do not really consider this necessary or a real security addition. Let's get rid of it thus, cleans up the code and makes the logic easier.

Use ISession::clear

The native approach using the PHP calls will not work properly with the cryptowrapper and thus this code is effectively doing nothing at the moment.

Use proper class name