Add version API

[ChrisDick]

Is your feature request related to a problem? Please describe.
emfcamp/badge-2024-software#106

Describe the solution you'd like
Add the API for version

Describe alternatives you've considered
Undocumented feature.

Additional context
There's the ota API that exposes the version from esp_ota_get_running_partition() as a string, but isn't documented. The update function doesn't need to be added as it's an internal API.
import ota
ota.get_version()
'v1.8.0'