Battery definition inside GDTF

[moritzstaffel]

Is your feature request related to a problem? Please describe. Some lamps have batteries that they can be powered with.

Describe the solution you'd like We need to describe for the fixture that:

• they have a battery
• how long it can run
• Map between runtime and light output

Describe alternatives you've considered

Additional context We also need to define if the lamp can be only used with the battery

[Verschwiegener]

Maybe a Battery Type(?) attribute would also be helpful to define how the battery is connected if it is soldered, user replaceable etc. -Soldered -Replaceable -Quick Swap -External(?)