This option allows user to specify a url prefix for owncloud.
By default it is set to "" and the document root will be set
to owncloud's dir.
If a prefix is set, e.g. urlPrefix = "/owncloud"
an alias will be created using that prefix to point to owncloud's
dir and owncloud will be available at http://localhost/owncloud
Rather than using openssl to hash the password at build time, and hence
leaving the plaintext password world-readable in the nix store, we can
instead hash the password in the nix expression itself using
builtins.hashString.
Augustin Borsu
Philip Potter
Matej Cotman