Add TypedInput for UI Gauge

[joepavitt]

Description

Many users face friction when using a gauge currently as the rendered value is always the full msg.payload sent. Often users want to round this to a whole number, or a fixed number of decimal places. Whilst we could just introduce a single "rounding" type property, this would be unique to the gauge.

Instead, we should do a small implementation here based on the work that @Steve-Mcl did in #1237. We should had a "value" property that is a Node-RED TypedInput. That would then allow users to use the JSONata type and include rounding, etc.

The server-side logic in the .js file then needs to process that TypedInput before the msg is sent to the client, and process the value. The client can then display the relevant result in the gauge.

Epic/Story

#555

Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate

[joepavitt]

Closed by #1752