Add: Introduce a release Command "interface"

Add abstract base classes representing sync and async release related
commands. This will allow to abstract the current sign and release
commands.

The base class also adds an error terminal and convenience methods for
printing errors and warnings to the error terminal.

pontos/release/command.py

@@ -0,0 +1,63 @@
+# SPDX-FileCopyrightText: 2023 Greenbone AG
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+import asyncio
+from abc import ABC, abstractmethod
+from typing import Any
+
+from pontos.terminal import Terminal
+
+
+class Command(ABC):
+    """Base class for release related command"""
+
+    def __init__(self, *, terminal: Terminal, error_terminal: Terminal) -> None:
+        self.terminal = terminal
+        self.error_terminal = error_terminal
+
+    def print_error(self, *messages: Any, **kwargs: Any) -> None:
+        """Print an error to the error terminal"""
+        self.error_terminal.error(*messages, **kwargs)
+
+    def print_warning(self, *messages: Any, **kwargs: Any) -> None:
+        """Print a warning to the error console"""
+        self.error_terminal.warning(*messages, **kwargs)
+
+    @abstractmethod
+    def run(self, **kwargs) -> int:
+        """Run the command"""
+
+
+class AsyncCommand(Command):
+    """Base class for release related commands using asyncio"""
+
+    def run(self, **kwargs) -> int:
+        """
+        Run the command using asyncio
+
+        MUST NOT be called when an asyncio event loop is already running.
+        """
+        return asyncio.run(self.async_run(**kwargs))
+
+    @abstractmethod
+    async def async_run(self, **kwargs) -> int:
+        """
+        Run the async command
+
+        Gets called via run. Alternatively use similar code as the example.
+
+        Example:
+            .. code-block:: python
+
+                import asyncio
+
+                async def main():
+                    cmd = MyAsyncCommand()
+                    task = asyncio.create_task(cmd.async_run(arg1, arg2))
+                    ...
+                    await task
+
+
+                asyncio.run(main())
+        """