[GitHub Templates] Added funding template

.github/FUNDING.yml

@@ -0,0 +1,5 @@
+# These are supported funding model platforms
+
+github: [andryyy]
+custom: https://liberapay.com/mailcow
+custom: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=JWBSYHF4SMC68