Change: Make messages translatable that occur early in start-up

These messages include the command-line messages (both errors and the
help text). To do this, the deprecated `--confdir` option has been
removed. This option was only used on windows before roaming profiles
were supported.

https://github.com/owncloud/client/issues/11142
https://github.com/owncloud/client/issues/11246
https://github.com/owncloud/client/pull/11300
