some ideas from bedhost refactor

[nsheff]

Just recording some ideas I've been having as I refactored bedhost

• [x] #75
• [x] in bedhost, functions in helpers.py are raising HTTP exceptions. Instead, I think HTTP exceptions (404 errors) should only be raised by the main fastapi functions/endpoints... the helper functions should standalone. Thus, they should raise other exceptions, which should be caught and raised as 404 HTTP errors by the fastapi functions.
• [x] related to this, some of these helper functions should move to bbconf. eg:
  • assert_table_columns_match
  • serve_schema_for_table
• [x] in bbc.bedset.select_distinct(table_name=BEDSET_TABLE,, it seems the BEDSET_TABLE information is really passed twice... once by the attribute bedset, and then again by table_name. instead, this should be passing pipeline_type. (which should default to sample, and therefore probably isn't even necessary...). So, does select_distinct really require table_name ?
• [x] the logic of the actual BED_TABLE and BEDSET_TABLE should be removed from bedhost. This should be abstracted away and be handled by pipestat.

[donaldcampbelljr]

pipestat's select_distinct no longer requires table_name as this is now an attribute of the pipestatmanager e.g. self.table_name We've also removed pipeline_type as this was being used to determine the table_name.

[khoroshevskyi]

Private_api will be deleted, because most of this endpoints were made for distance search. Now we are using qdrant, and search_router Router will be created