Make source items foldable

[ptar]

Currently, it might be very confusing to have a lot of source items, e.g. in Modbus.

Folding with a title consisting of the item values should really make it easier to work with.

It could work similar to this example (it should work like that, it doesn't have to look like that)

#2: InverterPower (U Short):5016

[See the 1. image below]

#3: GridPower (Short):13009

[See the 2. image below]

#4: HomeBatterySoc(U Short):13022

[See the 3. image below]

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Since images doesn't seem to work here in details, this is the example with all folds open:

• # 2: InverterPower (U Short):5016
  

• # 3: GridPower (Short):13009
  

• # 4: HomeBatterySoc(U Short):13022