Toggl2moneybird

- Fix 'billable' KeyError that sometimes occurs when syncing modified description
- Allow running when rich_argparse is not installed

Fix an error that only occurs on July 31st or the last few days of May

- Rename `--unbillable` option to `--include-unbillable` for clarity
- That option no longer looks at the Billable flag on a project, only on individual entries (see 4)
- Add `erase` command for deleting synchronized entries from moneybird (`--project` can be added to only delete entries for a particular project)
- Add `logout` command, which forgets Toggl Track and moneybird credentials
- Add `login` command for symmetry

Fixes 3, which causes an exception when syncing time entries associated with archived projects.

Minor bug fixes, and improvements helping people without paid Toggl Track subscription:
- Add `--unbillable-tag` setting to mark everything as billable except those with a given tag (2)
- Now asks for hourly rate and currency when invoicing if it cannot determine so from Toggl Track workspace settings
- Add `--rate` and `--currency` settings to override the hourly rate and currency when invoicing
- Billable entries are now marked with an emoji in the mutations table
- Fix description not showing up in mutations table when not modified
- Fix problem listing draft invoices covering multiple periods

Adds the `--exclude-tag` flag which can be used to exclude time entries with a given tag from being synchronized.
Minor quality of life improvements.