Updated project structure and some file names.

Restored `requirements.txt`

Updated `setup.py` to include new repository url and contact details.

Moved the rtsp code from `record` to `stream`.

Updated project structure to make it more readable and developer friendly - moved mixins to the `mixins` package, moved handlers to the `handlers` package.

Moved files not belonging to anything in particular to the `util` package.

Updated `camera` class to also defer login call.

Deleted unused files like `config_handler`.

reolinkapi/mixins/user.py

@@ -0,0 +1,65 @@
+from typing import Dict
+
+
+class UserAPIMixin:
+    """User-related API calls."""
+    def get_online_user(self) -> Dict:
+        """
+        Return a list of current logged-in users in json format
+        See examples/response/GetOnline.json for example response data.
+        :return: response json
+        """
+        body = [{"cmd": "GetOnline", "action": 1, "param": {}}]
+        return self._execute_command('GetOnline', body)
+
+    def get_users(self) -> Dict:
+        """
+        Return a list of user accounts from the camera in json format.
+        See examples/response/GetUser.json for example response data.
+        :return: response json
+        """
+        body = [{"cmd": "GetUser", "action": 1, "param": {}}]
+        return self._execute_command('GetUser', body)
+
+    def add_user(self, username: str, password: str, level: str = "guest") -> bool:
+        """
+        Add a new user account to the camera
+        :param username: The user's username
+        :param password: The user's password
+        :param level: The privilege level 'guest' or 'admin'. Default is 'guest'
+        :return: whether the user was added successfully
+        """
+        body = [{"cmd": "AddUser", "action": 0,
+                 "param": {"User": {"userName": username, "password": password, "level": level}}}]
+        r_data = self._execute_command('AddUser', body)[0]
+        if r_data["value"]["rspCode"] == 200:
+            return True
+        print("Could not add user. Camera responded with:", r_data["value"])
+        return False
+
+    def modify_user(self, username: str, password: str) -> bool:
+        """
+        Modify the user's password by specifying their username
+        :param username: The user which would want to be modified
+        :param password: The new password
+        :return: whether the user was modified successfully
+        """
+        body = [{"cmd": "ModifyUser", "action": 0, "param": {"User": {"userName": username, "password": password}}}]
+        r_data = self._execute_command('ModifyUser', body)[0]
+        if r_data["value"]["rspCode"] == 200:
+            return True
+        print(f"Could not modify user: {username}\nCamera responded with: {r_data['value']}")
+        return False
+
+    def delete_user(self, username: str) -> bool:
+        """
+        Delete a user by specifying their username
+        :param username: The user which would want to be deleted
+        :return: whether the user was deleted successfully
+        """
+        body = [{"cmd": "DelUser", "action": 0, "param": {"User": {"userName": username}}}]
+        r_data = self._execute_command('DelUser', body)[0]
+        if r_data["value"]["rspCode"] == 200:
+            return True
+        print(f"Could not delete user: {username}\nCamera responded with: {r_data['value']}")
+        return False