Refactor czi_hosted and server into backend directory, pull common code into backend/common, refactor tests (#2102)

* move local_server -> backend/server server-> backend/czi_hosted, pull common code into backend/common update imports, tests and make commands

backend/server/auth/auth_session.py

@@ -0,0 +1,39 @@
+from backend.server.auth.auth import AuthTypeBase, AuthTypeFactory
+from flask import session
+from uuid import uuid4
+
+
+class AuthTypeSession(AuthTypeBase):
+    """Session based authentication.  The user is always logged.  The user id is a random number
+    associated with the session.  This is a good choice for desktop servers."""
+
+    # key in the session token for userid
+    CXGUID = "cxguid"
+
+    def __init__(self, app_config):
+        super().__init__()
+
+    def is_valid_authentication_type(self):
+        return True
+
+    def complete_setup(self, app):
+        pass
+
+    def is_user_authenticated(self):
+        # always authenticated
+        return True
+
+    def get_user_id(self):
+        if self.CXGUID not in session:
+            session[self.CXGUID] = uuid4().hex
+            session.permanent = True
+        return session[self.CXGUID]
+
+    def get_user_name(self):
+        return "anonymous"
+
+    def get_user_email(self):
+        return None
+
+
+AuthTypeFactory.register("session", AuthTypeSession)