Programmatic (Mustache) Titles & Labels

### Description

Great work with Dashboard 2.0, loving it so far...

One of the things I believe is missing (or I have misunderstood) is the ability to support dynamic titles, labels, etc... in all widgets... in general... this is achieved by angular filters. Not experienced enough to see if there is anything similar in vue.js.

Quoting original documentation of dashboard 1.0 (https://flows.nodered.org/node/node-red-dashboard)

> Most widgets can have a label and value - both of these can be specified by properties of the incoming msg if required, and modified by angular filters. For example the label can be set to {{msg.topic}}, or the value could be set to {{value | number:1}}% to round the value to one decimal place and append a % sign.

That way the title of a chart, or title of a gauge can be adjusted dynamically by easily parsing incoming payload...

### Have you provided an initial effort estimate for this issue?

I am no FlowFuse team member