For user setups, a number of dirs are used, whose paths are
customizable.

For workdir, before:
- $WEBOOB_WORKDIR
- $XDG_CONFIG_HOME/weboob

and after:
- $WOOB_WORKDIR
- $WEBOOB_WORKDIR
- $XDG_CONFIG_HOME/woob
- $XDG_CONFIG_HOME/weboob

If the old name is found in $XDG_CONFIG_HOME, it will try to rename it.

For data dir, now:
- $WOOB_DATADIR
- $WOOB_WORKDIR
- $WEBOOB_DATADIR
- $WEBOOB_WORKDIR
- $XDG_DATA_HOME/woob
- $XDG_DATA_HOME/weboob

Also, $WOOB_BACKENDS then $WEBOOB_BACKENDS.