template for monitormysolar dongle

[skrul]

This PR adds a meter template for the monitormysolar dongle (https://monitormy.solar/detail/13) which gives evcc access to LUX inverters (and others in the future). This template provides grid, pv, and battery data as well as battery control support.

Sample config:

meters:
  - name: my_grid
    type: template
    template: monitormysolar
    usage: grid
    dongleId: dongle-40:4C:CA:xx:xx:xx
  - name: my_pv
    type: template
    template: monitormysolar
    usage: pv
    dongleId: dongle-40:4C:CA:xx:xx:xx
  - name: my_battery
    type: template
    template: monitormysolar
    usage: battery
    dongleId: dongle-40:4C:CA:xx:xx:xx
    dongleHost: e06d094c-1fa7-4fb7-80ee-b250dce7ea49.mock.pstmn.io

Sample meter output:

$ ./evcc -c ./evcc.yaml meter
[main  ] INFO 2025/01/08 16:44:01 evcc b728e23c (b728e23c)
[main  ] INFO 2025/01/08 16:44:01 using config file: ./evcc.yaml
[db    ] INFO 2025/01/08 16:44:01 using sqlite database: /Users/skrul/.evcc/evcc.db
[mqtt  ] INFO 2025/01/08 16:44:01 connecting evcc-2068687641 at tcp://10.0.0.101:1883
[mqtt  ] DEBUG 2025/01/08 16:44:01 tcp://10.0.0.101:1883 connected
my_grid
-------
Power:  0W
Energy: 10.9kWh

my_pv
-----
Power:  107W
Energy: 19.8kWh

my_battery
----------
Power:        234W
Energy:       3.0kWh
Soc:          97%
Controllable: true

[skrul]

@andig turns out the dongle author decided to implement the battery control stuff using an HTTP endpoint rather than MQTT so this simplifies everything, and made it possible to implement this as a template. This is still a bit of a work in progress because the new HTTP API isn't quite finalized but it will be pretty close to this.