feat: validate configuration

src/config/fixtures/test_config.toml

@@ -0,0 +1,28 @@
+[bitmagnet]
+enable = true
+host = "http://localhost:8080"
+
+[transmission]
+enable = false
+host = "localhost"
+port = 9091
+username = "admin"
+password = "password"
+download_dir = "/downloads"
+
+[ntfy]
+enable = true
+topic = "reddit-magnet"
+host = "https://ntfy.sh"
+priority = "default"
+
+[sources.movies]
+username = "movie_poster"
+title_filter = "\\[1080p\\]"
+tags = ["movies", "hd"]
+
+[sources.tv_shows]
+username = "tv_shows_fan"
+title_filter = "S\\d{2}E\\d{2}"
+imdb_id = "tt1234567"
+tags = ["tv", "series"]