move podcasts to within nested podcasts folder (significant breaking change)

src/folders.rs

@@ -0,0 +1,12 @@
+use std::path;
+
+use sanitise_file_name::sanitise;
+
+pub(crate) const PODCASTS_DIR: &str = "Podcasts";
+
+pub(crate) fn podcast_folder(
+    root: &path::Path,
+    alias: &str,
+) -> path::PathBuf {
+    root.join(PODCASTS_DIR).join(sanitise(alias))
+}