mini-widget: display a location

### Problem to solve

Sometimes it's useful to track/record the numerical values of a location, rather than just visualising its position on a map, and sometimes locations are not geo-referenced. Currently this is awkward to do, because it requires multiple separate mini-widgets and the data may not be in the desired display format (e.g. see #1326).

### Desired approach

A mini-widget with support for
1. any valid sources of location data
- MAVLink / NMEA / etc
- vehicle location, control station location, etc
2. common display formats
- latitude, longitude
- [UTM](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system)
- local x, y [,z] (probably with support for metric vs imperial)
3. position validity/accuracy
- colour or opacity could potentially be used to indicate when a position estimate is uncertain, or older than a threshold time

### Additional context

- [Lat, Lng Issue](https://github.com/bluerobotics/cockpit/issues/992) as part of a broader VGI discussion
- [UTM request and discussion](https://discuss.bluerobotics.com/t/utm-format-position-display-in-cockpit-qgc-for-recording/18008)

### Prerequisites

- [X] I have checked to make sure that a similar request has not already been filed or fixed.

Start by reviewing the existing mini-widgets, issue #1326, the linked latitude/longitude issue #992, and the UTM discussion. The scope needs clarification around supported location sources, display formats, units, and validity indicators before implementation can begin; done would be a defined widget covering the agreed requirements.

Written by the indexing model from the issue text.