ari: User better nicknames for ARI operations

While working on building client libraries from the Swagger API, I
noticed a problem with the nicknames.

    channel.deleteChannel()
    channel.answerChannel()
    channel.muteChannel()

Etc. We put the object name in the nickname (since we were generating C
code), but it makes OO generators redundant.

This patch makes the nicknames more OO friendly. This resulted in a lot
of name changing within the res_ari_*.so modules, but not much else.

There were a couple of other fixed I made in the process.

 * When reversible operations (POST /hold, POST /unhold) were made more
   RESTful (POST /hold, DELETE /unhold), the path for the second operation
   was left in the API declaration. This worked, but really the two
   operations should have been on the same API.
 * The POST /unmute operation had still not been REST-ified.

Review: https://reviewboard.asterisk.org/r/2940/
........

Merged revisions 402528 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@402529 65c4cc65-6c06-0410-ace0-fbb531ad65f3

rest-api/api-docs/applications.json

@@ -14,7 +14,7 @@
 				{
 					"httpMethod": "GET",
 					"summary": "List all applications.",
-					"nickname": "getApplications",
+					"nickname": "list",
 					"responseClass": "List[Application]"
 				}
 			]
@@ -26,7 +26,7 @@
 				{
 					"httpMethod": "GET",
 					"summary": "Get details of an application.",
-					"nickname": "getApplication",
+					"nickname": "get",
 					"responseClass": "Application",
 					"parameters": [
 						{
@@ -55,7 +55,7 @@
 					"httpMethod": "POST",
 					"summary": "Subscribe an application to a event source.",
 					"notes": "Returns the state of the application after the subscriptions have changed",
-					"nickname": "applicationSubscribe",
+					"nickname": "subscribe",
 					"responseClass": "Application",
 					"parameters": [
 						{
@@ -94,7 +94,7 @@
 					"httpMethod": "DELETE",
 					"summary": "Unsubscribe an application from an event source.",
 					"notes": "Returns the state of the application after the subscriptions have changed",
-					"nickname": "applicationUnsubscribe",
+					"nickname": "unsubscribe",
 					"responseClass": "Application",
 					"parameters": [
 						{