Miteclock

- Update mite URL to reflect the webapp's new domain.
- Test and document support for Pythonn 3.11.
- Pin direct dependencies. This reduces the likelihood of bugs and problems due to
differences in installed packages.
- Development changes: introduce bumpver tool to manage versions, expand test coverage.

- Rename `client` field to `customer` to be more consistent with mite terminology. This
breaks compatibility, for that I apologize. I hope the damage is minimal, however,
since the feature is new and has not been adopted yet as far as I know.
- Include customer information in reports and error messages with projects.
- Documentation for advanced pattern definitions.

- Fix field name for retrieving client/customer name.

- Support omitting the note part of an activity and leaving project or service empty, as
described in [4](https://github.com/iliakur/miteclock/issues/4)
- Support selecting projects based also on client name, as requested in
[5](https://github.com/iliakur/miteclock/issues/5).
- Switch to CalVer scheme. This way we follow an established convention that
communicates clearly.

- Fix crash at initialization if config folder does not exist. See issue 3.
- Fix crash of `m status` if entries without project or service name are present.

- Extended test coverage, found and fixed a bug in `m status` as a result.
- Reworked documentation in README, CHANGELOG and help messages.