Move envisalink component to package and add services.yaml (#19731)

* Moved component to a package and added a services.yaml file.

* Fixing coverage issue and grammar issue on the services.yaml file.

* Fixed typo in the services.yaml file.

.coveragerc

@@ -106,7 +106,7 @@ omit =
     homeassistant/components/enocean.py
     homeassistant/components/*/enocean.py
 
-    homeassistant/components/envisalink.py
+    homeassistant/components/envisalink/__init__.py
     homeassistant/components/*/envisalink.py
 
     homeassistant/components/evohome.py

homeassistant/components/envisalink/services.yaml

@@ -0,0 +1,15 @@
+# Describes the format for available Envisalink services.
+
+invoke_custom_function:
+  description: >
+    Allows users with DSC panels to trigger a PGM output (1-4).
+    Note that you need to specify the alarm panel's "code" parameter for this to work.
+  fields:
+    partition:
+      description: >
+        The alarm panel partition to trigger the PGM output on.
+        Typically this is just "1".
+      example: "1"
+    pgm:
+      description: The PGM number to trigger on the alarm panel. This will be 1-4.
+      example: "2"