Squashed commit of the following:

commit 56f5f5a6cbad595534148a160678972734ca6cf2
Author: Ricki Hirner <hirner@bitfire.at>
Date:   Wed Sep 29 10:59:23 2021 +0200

    Version bump to 4.0-beta1

commit 2a4d7501d9d6cd572269de21e82c204c5a2a57e8
Author: Ricki Hirner <hirner@bitfire.at>
Date:   Tue Sep 28 21:45:49 2021 +0200

    Fix UiUtils.launchUri once again

commit 293accaf8f26842d198e9d5c4fc9029cb6ac71cc
Author: Ricki Hirner <hirner@bitfire.at>
Date:   Tue Sep 28 13:47:06 2021 +0200

    Adjust gradle daemon heap size

commit 7763a51c9bbc7baee36ef71648889f7fb4fe965d
Author: Ricki Hirner <hirner@bitfire.at>
Date:   Tue Sep 28 12:21:37 2021 +0200

    Query and show quota

commit 95f4dbfd8ffadd930aab9fc36dc3865bfee54fb7
Author: Ricki Hirner <hirner@bitfire.at>
Date:   Mon Sep 27 22:16:48 2021 +0200

    Persist cookies over WebDAV sessions

commit 17c9327eb3ef3d9384b28b70aa9637718d34e8a2
Author: Ricki Hirner <hirner@bitfire.at>
Date:   Sun Sep 26 19:54:57 2021 +0200

    Add WebDAV caches

    * add random access page cache
    * add thumbnail cache
    * add HEAD response cache

commit 0e5237f8b178ab66099999f72e657c59c9302d71
Author: Ricki Hirner <hirner@bitfire.at>
Date:   Tue Aug 31 13:25:36 2021 +0200

    Add WebDAV Access over Storage Access Framework