feat(cli): add command to generate systemd unit files

- Introduces a CLI tool for creating systemd .timer and .service units
- Adds options for configuring unit names, commands, scheduling, and more
- Supports dry-run mode and user-level unit file generation

src/cli/main.ts

@@ -0,0 +1,9 @@
+import { Command } from '@cliffy/command';
+import { createCommand } from './create.ts';
+
+await new Command()
+    .name('systemd-timer')
+    .version('0.1.0')
+    .description('CLI Tool zum Erzeugen von systemd .timer und .service Units')
+    .command('create', createCommand)
+    .parse(Deno.args);