Break APIs into its own modules

Author: npalaska

lib/pbench/cli/server/shell.py

@@ -1,12 +1,11 @@
 #!/bin/env python3
 
-from pbench.server.api import App
+from pbench.server.api import create_app
 import subprocess
 
 
 def main():
-    flask_app = App()
-    app = flask_app.create_app()
+    app = create_app()
     port = app.config["PORT"]
     host = app.config["BIND_HOST"]
     workers = app.config["WORKERS"]
@@ -19,6 +18,6 @@ def main():
             "/run/pbench-server/gunicorn.pid",
             "--bind",
             f"{str(host)}:{str(port)}",
-            "pbench.server.api:App.create_app()",
+            "pbench.server.api:create_app()",
         ]
     )