Adding Support for EG4-LL 12v BMS

[tuxntoast]

Adding a driver for EG4-LL 12v BMS.

• Add your battery class and battery class import in alphabetical order in the etc/dbus-serialbattery/dbus-serialbattery.py
• Add your BMS to the BMS feature comparison page by editing docs/docs/general/features.md
• Add your BMS to the Supported BMS page by editing docs/docs/general/supported-bms.md
• Do not import wildcards *
• If available populate self.max_battery_charge_current and self.max_battery_discharge_current with values read from the BMS
• If available populate self.unique_identifier with a unique value to distinguish the BMS in a multiple battery setup
• If your BMS don't run with the default settings add installation notes to the How to install, update, disable, enable and uninstall docs/docs/general/install.md
• If your BMS needs custom settings that the user should be able to change, add it below the ; --------- BMS specific settings --------- section in the etc/dbus-serialbattery/config.default.ini
• Make sure the GitHub Actions run fine in your repository. In order to make the GitHub Actions run please select in your repository settings under Actions -> General -> Actions permissions the option Allow all actions and reusable workflows. Check also in your repository settings under Actions -> General -> Workflow permissions if Read and write permissions are selected. After this changes you have to make a new commit, if you don't see any Actions run. This will check your code for Flake8 and Black Lint errors. Here is a short instruction on how to set up Flake8 and Black Lint checks in VS Code. This will save you a lot of time.

[mr-manuel]

Please use this checklist: https://louisvdw.github.io/dbus-serialbattery/general/supported-bms#add-by-opening-a-pull-request