Enhancement: Loading context blocks application bootstrap

The bootstrap architecture has been improved to ensure that the respective context (user or public link)
is fully resolved before applications can finalize their boot process and switch over to rendering their content.
This means that application developers can rely on user data / public link data being loaded (including
e.g. capabilities) when the web runtime triggers the boot processes and rendering of applications.

https://github.com/owncloud/web/issues/7030
https://github.com/owncloud/web/pull/7072
