Smarthomeconnect

- New decorator [expression](https://smarthomeconnect.readthedocs.io/en/latest/variables_expressions.html#shc.expressions.expression) for creating SHC expressions from simple Python functions
- New [Multiplexer](https://smarthomeconnect.readthedocs.io/en/latest/variables_expressions.html#shc.expressions.Multiplexer) expression
- New [Ramp generators](https://smarthomeconnect.readthedocs.io/en/latest/timer.html#ramp-generators)
- New interface [Ping](https://smarthomeconnect.readthedocs.io/en/latest/interfaces/misc.html#ping)
- New [energy sensor connectors](https://smarthomeconnect.readthedocs.io/en/latest/interfaces/tasmota.html#shc.interfaces.tasmota.TasmotaInterface.energy_power) for Tasmota interface
- Frontend web assets are now pulled from NPM and bundled with Parcel.js when building the Python distribution
- Updated frontend web asset versions
- Updated Python dependency versions, esp. adding support for Jinja2 3.x.

Fixes
- `shc.handler()` decorator does not mistake Expressions in the origin for recursive execution of the handler anymore

Major changes (probably breaking)

* Rework of subscription system (asynchronous publishing, `_publish` is no coroutine anymore, origin clearing for state consistency)
* Interfaces' `wait()` method dropped
* `persistence` module renamed to `log` and completely refactored

Other major changes
* New SHC websockt client interface
* New MQTT & Tasmota interfaces
* New web UI widgets for logging
* New helper classes (e.g. `Hysteresis`, `TimerSwitch`, `BreakableSubscription`)

… and many, many minor changes and fixes