add `READSB_ENABLE_HEATMAP` , do some clean-up #761

Job	Run time
Triggered via Workflow Dispatch?	0s
Deploy with telegraf and healthcheck / Prepare workflow environment	9s
Deploy without telegraf / Prepare workflow environment	11s
Deploy with telegraf and healthcheck / Build (manifest)	5m 3s
Deploy with telegraf and healthcheck / Build nohealthcheck (manifest)	5m 23s
Deploy with telegraf and healthcheck / Build	0s
Deploy with telegraf and healthcheck / Build nohealthcheck	0s
Deploy without telegraf / Build nohealthcheck (linux/arm/v7)	3m 1s
Deploy without telegraf / Build nohealthcheck (linux/arm64)	3m 27s
Deploy without telegraf / Build (manifest)	4m 6s
Deploy without telegraf / Build nohealthcheck (linux/amd64)	1m 32s
Deploy without telegraf / Build (linux/arm/v7)	2m 35s
Deploy without telegraf / Build (linux/arm64)	2m 44s
Deploy without telegraf / Build (linux/amd64)	1m 34s
Deploy without telegraf / Build nohealthcheck (manifest)	4m 32s
Trigger deploy of sdr-enthusiasts/docker-adsb-ultrafeeder	15s
	34m 32s

Provide feedback