Add command and state helper functions

[iMicknl]

In Home Assistant there is code to check for states and commands, and to retrieve them. This should be included in the underlying library as it is useful for all use-cases.

    def select_command(self, *commands: str) -> str | None:
        """Select first existing command in a list of commands."""
        existing_commands = self.device.definition.commands
        return next((c for c in commands if c in existing_commands), None)

    def has_command(self, *commands: str) -> bool:
        """Return True if a command exists in a list of commands."""
        return self.select_command(*commands) is not None

    def select_definition_state(self, *states: str) -> StateDefinition | None:
        """Select first existing definition state in a list of states."""
        for existing_state in self.device.definition.states:
            if existing_state.qualified_name in states:
                return existing_state
        return None

    def select_state(self, *states: str) -> OverkizStateType:
        """Select first existing active state in a list of states."""
        for state in states:
            if current_state := self.device.states[state]:
                return current_state.value

        return None

    def has_state(self, *states: str) -> bool:
        """Return True if a state exists in self."""
        return self.select_state(*states) is not None

    def select_attribute(self, *attributes: str) -> OverkizStateType:
        """Select first existing active state in a list of states."""
        for attribute in attributes:
            if current_attribute := self.device.attributes[attribute]:
                return current_attribute.value

        return None