Add Vehicle Config UI Tab and SoC display

[glynhudson]

After #67 is merged we should make a 'Vehicle' tab on the web UI interface to interface with the Tesla integration e.g set enter username / password etc. I've added the API call for the Tesla integration as a comment in #67

The vehicle tab should be structured to allow for multiple vehicle integrations, probably with only a single integration being used at a time..for the moment.

Once the vehicle integration is active the current vehicle SoC can be displayed on the main page, it would probably be a good idea to provide an indicator as to when this was last updated (like we currently with solar PV divert).

OVMS should be the next integration to consider adding.

[Pukkahq]

I have not tested this in the last few years but this might help for the BMW
https://github.com/openenergymonitor/emonhub/tree/emon-pi/conf/interfacer_examples/bmw

[Pukkahq]

just been and added the interface yes it still works

[glynhudson]

The GUI looks great, however where is the MQTT topic for SoC set? Or is this pre-set to a particular topic? If this is the case the GUI should have an info box to let the user know what topic to use for SoC

[jeremypoulter]

Not quite sure I understand the issue, your screen shot has the input field for the SoC topic, is it not clear that you should enter a topic name?

[glynhudson]

Apologies, my mistake, I didn't realise the fields where for topic names. I figured it out, working now :-)

To make it obvious I've added the word 'topic' as a suffix to the field labels: OpenEVSE/openevse_wifi_gui@a50ad77