Either ESP32 rev1/2 that needs special fixes
`-DHAS_PSRAM_FIX -mfix-esp32-psram-cache-issue -lc-psram-workaround -lm-psram-workaround`
or ESP32-PICO-V3-02 that requires esp-idf 4.4
The device name can be useful to identify a particular instance in
Prometheus.
Example:
```
tasmota_info{...,devicename="livingroom"} 1
```
Signed-off-by: Michael Hanselmann <public@hansmi.ch>
This was a problem for me when trying to get output from an SDS011 Nova
PM sensor. When parsed by the pometheus code it returns labels / metrics
like:
```# TYPE tasmota_sensors_pm2.5_ gauge
tasmota_sensors_pm2.5_{sensor="sds0x1"} 2.2```
The error from prometheus was:
```"append failed" err="invalid metric type \\"5_ gauge\\"```
Exports version, image type, and build timestamp.
It's common to export something like this to show version numbers across the fleet.
For example, the golang exporter exposes version:
```
go_info{version="go1.14.4"} 1
```
And prometheus exposes:
```
prometheus_build_info{branch="HEAD",goversion="go1.14.4",revision="eba3fdcbf0d378b66600281903e3aab515732b39",version="2.19.1"} 1
```