Rename DbModels Embeddings, EmbeddingsAdapter to Entry, EntryAdapter

Improves readability as name has closer match to underlying
constructs

- Entry is any atomic item indexed by Khoj. This can be an org-mode
  entry, a markdown section, a PDF or Notion page etc.

- Embeddings are semantic vectors generated by the search ML model
  that encodes for meaning contained in an entries text.

- An "Entry" contains "Embeddings" vectors but also other metadata
  about the entry like filename etc.

tests/test_client.py

@@ -17,7 +17,7 @@ from khoj.search_type import text_search, image_search
 from khoj.utils.rawconfig import ContentConfig, SearchConfig
 from khoj.processor.org_mode.org_to_jsonl import OrgToJsonl
 from database.models import KhojUser
-from database.adapters import EmbeddingsAdapters
+from database.adapters import EntryAdapters
 
 
 # Test
@@ -178,7 +178,7 @@ def test_get_configured_types_via_api(client, sample_org_data):
     # Act
     text_search.setup(OrgToJsonl, sample_org_data, regenerate=False)
 
-    enabled_types = EmbeddingsAdapters.get_unique_file_types(user=None).all().values_list("file_type", flat=True)
+    enabled_types = EntryAdapters.get_unique_file_types(user=None).all().values_list("file_type", flat=True)
 
     # Assert
     assert list(enabled_types) == ["org"]