Default config for each search types to None

- Setting up default compressed-jsonl, embeddings-file was only required
  for org search_type, while org-files and org-filter were allowed to be
  passed as command line argument
- This avoided having to set compressed-jsonl and embeddings-file via
  command line argument as well for org search type
- Now that all search types are only configurable via config file, We
  can default all search types to None. The default config for the
  rest of the search types wasn't being used anyway

src/utils/cli.py

@@ -44,27 +44,11 @@ def cli(args=None):
 default_config = {
     'content-type':
     {
-        'org':
-        {
-            'compressed-jsonl': '.notes.jsonl.gz',
-            'embeddings-file': '.note_embeddings.pt'
-        },
-        'ledger':
-        {
-            'compressed-jsonl': '.transactions.jsonl.gz',
-            'embeddings-file': '.transaction_embeddings.pt'
-        },
-        'image':
-        {
-            'embeddings-file': '.image_embeddings.pt',
-            'batch-size': 50,
-            'use-xmp-metadata': 'no'
-        },
-        'music':
-        {
-            'compressed-jsonl': '.songs.jsonl.gz',
-            'embeddings-file': '.song_embeddings.pt'
-        },
+        'org': None,
+        'ledger': None,
+        'image': None,
+        'music': None,
+        'markdown': None,
     },
     'search-type':
     {