Pioreactor

- `pio update app` will default to installing the succeeding release of Pioreactor app, which may or may not be the latest. This is to ensure that no update script is skipped.
- Added new "Past Experiments" page
- Fix for "Reference photodiode is correct magnitude" self-test.

- Job growth_rate_calculating will dynamically choose initial values for its internal statistics.
- New entry in `stirring` section in config.ini: `use_rpm` (a boolean) can be used to engage or disengage the closed loop RPM system.
- Calibration structs change `timestamp` -> `created_at`.
- Backend work to complete calibrations utilities:
- Edits to the `calibrations` table in the database require a full drop and recreation.
- New API endpoints on the webserver to store calibrations, get calibrations, set as current, etc.
- New CLI: `pio run <x>_calibration publish` will publish a calibration to the webserver

- Python files in `plugins/` folder on leader are viewable on the /plugins page in the UI.
- Python files in `plugins/` folder on leader are uninstallable (aka deleted) on the /plugins page in the UI.
- `pio uninstall-plugin` will delete Python plugins in the .pioreactor/plugins/ dir if provided the _python file name_, sans `.py`.
- `pios reboot` should now work for the leader.
- Using the Pioreactor with an ethernet connection will provide the correct ip address.

- files in `~/.pioreactor/plugins` are now loaded lexographically. Previously it was up the the filesystem.
- Performance improvements for PioreactorUI
- Added new indexes to the SQLite database to improve read performance. This change will only impact new installs of Pioreactor.
- Improvements in error handling when plugins can't load.

Bug fixes
- fixed bug in adding new pioreactor not passing an avahi check.

- Removed the scaling difference between hardware versions in OD Reading.
- Moving some Python dependencies into this repo.
- More error handling around hardware versions
- fix `self_test.test_ambient_light_interference` test failing for HAT 1.1.

- fix bug in ending experiments not cleaning up automations properly.