Fix of the sidebar item highlight when matched by current search

Fix of the sidebar item highlight when matched by current search

Because searches done manually (or shifted with a window) have an
absolute path to the current Maildir within the URI, whereas the one
declared with the virtual-mailboxes command usually have implicit
Maildir path specification, this patch parses the given URL of a mailbox
and re-builds it to contain the full path.

For that purpose has been added:

- nm_normalize_uri() function

Has been modified:

- get_query_string (in mutt_notmuch): earned an argument to disable
  adding of a window in the context of the nm_normalize_uri function.
- mutt_parse_virtual_mailboxes: the path value is sent through the
  nm_normalize_uri() function to be normalized.

Signed-off-by: Guyzmo <guyzmo+github+pub@m0g.net>