Clean up module documentation (#36909)

* Clean up module documentation

This PR includes:
- Removal of `default: None` (and variations)
- Removal of `required: false`
- Fixing booleans and `type: bool` where required

* Fix remaining (new) validation issues

lib/ansible/modules/monitoring/icinga2_host.py

@@ -31,14 +31,14 @@ options:
     description:
       - If C(no), it will not use a proxy, even if one is defined in
         an environment variable on the target hosts.
-    default: 'yes'
     type: bool
+    default: 'yes'
   validate_certs:
     description:
       - If C(no), SSL certificates will not be validated. This should only be used
         on personally controlled sites using self-signed certificates.
-    default: 'yes'
     type: bool
+    default: 'yes'
   url_username:
     description:
       - The username for use in HTTP basic authentication.
@@ -53,8 +53,8 @@ options:
         responds to an initial request with a 401 status. Since some basic auth services do not properly
         send a 401, logins will fail. This option forces the sending of the Basic authentication header
         upon initial request.
-    default: 'no'
     type: bool
+    default: 'no'
   client_cert:
     description:
       - PEM formatted certificate chain file to be used for SSL client
@@ -68,7 +68,6 @@ options:
   state:
     description:
       - Apply feature state.
-    required: false
     choices: [ "present", "absent" ]
     default: present
   name:
@@ -82,17 +81,13 @@ options:
     description:
       - The template used to define the host.
       - Template cannot be modified after object creation.
-    required: false
-    default: None
   check_command:
     description:
       - The command used to check if the host is alive.
-    required: false
     default: "hostalive"
   display_name:
     description:
       - The name used to display the host.
-    required: false
     default: if none is give it is the value of the <name> parameter
   ip:
     description:
@@ -101,8 +96,6 @@ options:
   variables:
     description:
       - List of variables.
-    required: false
-    default: None
 '''
 
 EXAMPLES = '''