Downstream - removal of outdated API

[MorrisJobke]

Downstream of owncloud/core#28073

I will additionally also downstream owncloud/core#26539 to avoid update problems with the usage of this.

[nickvergessen]

Fine by me, as far as I know apps can provide ext. storages?

[MorrisJobke]

Fine by me, as far as I know apps can provide ext. storages?

Correct: https://github.com/icewind1991/files_external_ftp

[codecov]

Codecov Report

Merging #6146 into master will increase coverage by 0.16%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #6146      +/-   ##
============================================
+ Coverage     52.99%   53.15%   +0.16%     
+ Complexity    22697    22609      -88     
============================================
  Files          1407     1404       -3     
  Lines         87857    87594     -263     
  Branches       1327     1327              
============================================
+ Hits          46557    46560       +3     
+ Misses        41300    41034     -266

Impacted Files	Coverage Δ	Complexity Δ
apps/files_external/lib/AppInfo/Application.php	0% <ø> (ø)	4 <0> (ø)	⬇️
apps/comments/lib/EventHandler.php	79.16% <0%> (-8.34%)	7% <0%> (ø)
lib/private/Files/Cache/Propagator.php	94.93% <0%> (-1.27%)	16% <0%> (ø)
lib/private/Server.php	84.55% <0%> (-0.13%)	121% <0%> (ø)
apps/files_trashbin/lib/Trashbin.php	72.77% <0%> (+0.24%)	136% <0%> (ø)	⬇️
core/js/js.js	61.83% <0%> (+0.55%)	0% <0%> (ø)	⬇️
lib/private/Security/CertificateManager.php	92.07% <0%> (+0.99%)	39% <0%> (ø)	⬇️

[MorrisJobke]

Failure was due to missing sign-off - added and will merge it now.