Tihs makes it easier to use metrics based on device and folder labels,
names, and other attributes. Other metrics which are based on folder or
device ID can be joined with these info metrics to enrich their label
sets.
```
# HELP syncthing_config_device_info Provides additional information labels on devices
# TYPE syncthing_config_device_info gauge
syncthing_config_device_info{device="I6KAH76-66SLLLB-5PFXSOA-UFJCDZC-YAOMLEK-CP2GB32-BV5RQST-3PSROAU",introducer="false",name="s1",paused="false",untrusted="false"} 1
# HELP syncthing_config_folder_info Provides additional information labels on folders
# TYPE syncthing_config_folder_info gauge
syncthing_config_folder_info{folder="default",label="The default folder",path="s2",paused="false",type="sendreceive"} 1
```
With this you can e.g. query for
```
syncthing_connections_active * on(device) group_left syncthing_config_device_info
```
Fixes#9519Closes#10074Closes#10147
1fdf07933c