REST API endpoint streamlining and cleanup (#133)

* Consolidate engine_info api calls

* Change api methods to use POST when possible

* Delete engine API cleanup

* Remove redundant installed_engines endpoint

* Update proxy to use similar named methods to new API calls

* More API cleanup

* Jobs API cleanup

* More jobs API cleanup

* Fix add jobs error due to null queue

* Remove unnecessary full_status and snapshot API endpoints

* Streamline add job POST endpoint

* Fix test after method name change

server.py

@@ -58,15 +58,15 @@ class ZordonServer:
 
         # ---- Render Queue ----
         self.ctx.render_queue = RenderQueue()
-        self.ctx.render_queue.load_state(database_directory=Path(Config.upload_folder).expanduser())
         RenderQueue._default_instance = self.ctx.render_queue
         RenderQueue._sync_class()
+        RenderQueue.load_state(database_directory=Path(Config.upload_folder).expanduser())
 
         # ---- Distributed Job Manager ----
         self.ctx.distributed_job_manager = DistributedJobManager()
-        self.ctx.distributed_job_manager.subscribe_to_listener()
         DistributedJobManager._default_instance = self.ctx.distributed_job_manager
         DistributedJobManager._sync_class()
+        DistributedJobManager.subscribe_to_listener()
 
         self.api_server = None
         self.server_hostname: str = socket.gethostname()