The new `database search-journals` command allows searching journals by author, title, date and content. The old
submissions search command is now called `search-submissions`.
The help message and readme have been fixed and missing information has been added.
The output of the `download users` command has been generalised, so it does not use "submissions" even when downloading
journals; uses "items" instead.
Changes
* Add database command to search journals
Fixes
* Fix missing information in help message and readme
* Fix output of download users command not being generalised