TECH: Use get_plugin_config() instead of template sensor TZ in package.yaml

[ArdJonker]

get_plugin_config() provides:

• Currency
• Timezone
• Length (km)
• Name of HA instance (replace from v2g_liberty.py)
• Country (pre-select for electricity-providers?)

Use in globals:

config = await self.get_plugin_config()

Replaces:

template:
  - sensor:
    # To make the HA time_zone available to the V2G Liberty python code.
    - name: Time Zone
      unique_id: time_zone
      state: "{{ now().tzinfo }}"