added welcome email after subscription #498

Job	Run time
vars	1s
docker / docker	1m 3s
electron / electron (macos-latest)	6m 52s
tests / api-e2e-test	4m 51s
electron / electron (ubuntu-latest)	10m 11s
sites / Deploy sites	7m 42s
electron / electron (windows-latest)	16m 25s
tests / e2e-test (macos-latest)	6m 48s
tests / e2e-test (ubuntu-latest)	5m 42s
tests / test (macos-latest)	15m 10s
tests / test (ubuntu-latest)	12m 52s
	1h 27m 37s

Provide feedback