Theming: Add icon caching
Theming: Add icon caching

Signed-off-by: Julius Haertl <bf353fa4999f2f148afcc6d8ee6cb1ee74cc07c3@bitgrid.net>

xx621998xx/server,nextcloud/server,pmattern/server,whitekiba/server,Ardinis/server,pixelipo/server,Ardinis/server,pixelipo/server,pixelipo/server,endsguy/server,endsguy/server,michaelletzgus/nextcloud-server,xx621998xx/server,jbicha/server,nextcloud/server,xx621998xx/server,pixelipo/server,nextcloud/server,whitekiba/server,xx621998xx/server,andreas-p/nextcloud-server,nextcloud/server,jbicha/server,endsguy/server,whitekiba/server,pmattern/server,jbicha/server,jbicha/server,andreas-p/nextcloud-server,whitekiba/server,pixelipo/server,Ardinis/server,andreas-p/nextcloud-server,endsguy/server,Ardinis/server,pmattern/server,andreas-p/nextcloud-server,whitekiba/server,michaelletzgus/nextcloud-server,jbicha/server,michaelletzgus/nextcloud-server,endsguy/server,pmattern/server,pmattern/server,xx621998xx/server,michaelletzgus/nextcloud-server,Ardinis/server,andreas-p/nextcloud-server