[Stable12] fix scss webroot and url rewrite

[skjnldsv]

Backport of #7631

Allow scss to proberly work and cache file whatever situation they're in:

• Sub-directory nc installation
• Sub-directory nc installation with a non-root app_path
• Basic nc installation with a non-root path

[codecov]

Codecov Report

Merging #7688 into stable12 will decrease coverage by 16.66%.
The diff coverage is 0%.

@@ Coverage Diff @@## stable12 #7688 +/- ##
===============================================
- Coverage 53.92% 37.26% -16.67% 
Complexity 22712 22712 ===============================================
Files 1385 1385 Lines 86996 86998 +2 Branches 1330 1330 ===============================================
- Hits 46913 32416 -14497 - Misses 40083 54582 +14499

Impacted Files	Coverage Δ	Complexity Δ
lib/private/Template/CSSResourceLocator.php	0% <0%> (-72.14%)	26 <0> (ø)
lib/private/Template/SCSSCacher.php	6.29% <0%> (-63.31%)	35 <3> (ø)
...yption/Exceptions/ModuleAlreadyExistsException.php	0% <0%> (-100%)	1% <0%> (ø)
lib/private/App/CodeChecker/EmptyCheck.php	0% <0%> (-100%)	6% <0%> (ø)
...pps/files/lib/Activity/Settings/FavoriteAction.php	0% <0%> (-100%)	8% <0%> (ø)
...mments/tests/Unit/Controller/NotificationsTest.php	0% <0%> (-100%)	4% <0%> (ø)
apps/systemtags/lib/Settings/Admin.php	0% <0%> (-100%)	3% <0%> (ø)
...ddleware/Security/Exceptions/NotAdminException.php	0% <0%> (-100%)	1% <0%> (ø)
apps/dav/lib/CalDAV/Activity/Setting/Calendar.php	0% <0%> (-100%)	8% <0%> (ø)
.../Exceptions/EncryptionHeaderKeyExistsException.php	0% <0%> (-100%)	1% <0%> (ø)
... and 481 more

[juliusknorr]

@skjnldsv This breaks core icons after changing the color value in the theming app (what triggers rebuilding the core scss):

.icon-settings {
background-image: url('//core/css/../img/actions/settings.svg?v=1');
}

Also happens on master after #7631 🙈

[juliusknorr]

See comment.

[skjnldsv]

@juliushaertl Hum, strange, I fixed it though. I don't get why there was this error.
Could you check again?

[juliusknorr]

Opened #7704 so we don't forget to fix that on master as well.

[kyrofa]

I see what @juliushaertl is saying on the snap as well (but not in 12.0.4). Assuming that wasn't introduced in this PR (was it?), +1 from me. I see no behavioral change other than that.

[kyrofa]

Oh wait, #7631 was this PR to master, huh. Doh! That means this PR does introduce this behavior.

[skjnldsv]

@kyrofa yes! :p
Let me check

[skjnldsv]

@juliushaertl can you check again, Maybe we could get rid of the cache reset now that it will proberly erase the files when compiling again? :)

[juliusknorr]

@kyrofa Please have another look :)

Maybe we could get rid of the cache reset now that it will proberly erase the files when compiling again? :)

I don't think so, since we only detect changed variables globally and not per file, we need to make sure that all scss files are invalidated when variables change.

[skjnldsv]

@juliushaertl Okay here for me! :)

[kyrofa]

There we go, that seems to work perfectly, even when changing the theme color.