Add cache control configuration and initialization

[Lenart12]

Implements #80

[wimaha]

Thank you! I think this could work. I uploaded the version including this PR to dev tag on docker. Could you test it?

[Lenart12]

Tested dev branch (set cacheMaxAge=30 in env) together with master evcc branch

services:
  tesla-ble-http-proxy:
    image: wimaha/tesla-ble-http-proxy:dev
    environment:
      - cacheMaxAge=30 # Important to set this to anything more than 0
      - httpListenAddress=:5687
    container_name: tesla-ble-http-proxy
    volumes:
      - ~/TeslaBleHttpProxy/key:/key
      - /var/run/dbus:/var/run/dbus
    restart: always
    privileged: true
    network_mode: host
    cap_add:
      - NET_ADMIN
      - SYS_ADMIN
    ports:
      - "5687:8080"

and evcc snipet

# ...
interval: 3s
# ...
vehicles:
  - name: vehicle_1
    title: blauer e-Golf
    type: custom
    soc:
      source: http
      uri: http://etera:5687/api/1/vehicles/xxx/vehicle_data?endpoints=charge_state
      method: GET
      jq: .response.response.charge_state.battery_level
      timeout: 30s 
      # cache: 30s # <--- this is not set as it would only mess with the second layer of caching provided by evcc
    range:
      source: http
      uri: http://etera:5687/api/1/vehicles/xxx/vehicle_data?endpoints=charge_state
      method: GET
      jq: .response.response.charge_state.battery_range
      timeout: 30s 
    capacity: 44
# ...

And success, looks like caching is working :^)

It might be worth to consider the default value of cache max age, right now its 0 but maybe it would be good to either set it to maybe 5s; or add documentation how to run it with different settings.

[wimaha]

I will leave the cache to default 0 and updated the readme.

[wimaha]

Thank you for testing!

[Lenart12]

Is it not only "debug" or ""?

[wimaha]

oh, the other options are available but not implemented.

[wimaha]

I've updated the readme. Thank you!