feat: add custom DBC attributes

[t-bre]

Changes

• Custom DBC attributes to enable/disable telemetry and define PDU IDs.
• Constant defining CAN handler table size for on-car telemetry.
• PDU identifiers based on custom DBC attribute values now added to CAN handler table.

Related Issue(s)

Closes #8
Closes #16
Closes #18

Additional Notes

Now possible to do #13, we will just need to decide on the prioritisation.

[t-bre]

@AndreasDemenagas does it matter how the PDUs are sorted in the server schemas? The current code doesn't necessarily put them in increasing PDU ID order, though perhaps this would be easier to read if looking at the schema?

[rureverek]

Looks OK.

[AndreasDemenagas]

@AndreasDemenagas does it matter how the PDUs are sorted in the server schemas? The current code doesn't necessarily put them in increasing PDU ID order, though perhaps this would be easier to read if looking at the schema?

@t-bre No, it does not. The first PDUs in the schema file are the first ones to be shown in the GUI, but this can be changed and we can add our own ordering with just some custom properties on the schema :)