legacy: bibindex admin fix

Adds all the legacy admin interfaces to the `/admin` page, under the same category, so they are easily reachable. 
221:19: F821 undefined name 'get_oai_src_by_id'
445: D401 First line should be imperative: 'create', not 'creates'
445: D400 First line should end with '.', not 'e'
445: D200 One-line docstring should not occupy 2 lines
500: D400 First line should end with '.', not 'e'
536: D401 First line should be imperative: 'Return', not 'Returns'
536: D200 One-line docstring should not occupy 3 lines
631:9: F841 local variable 'sets_names' is assigned to but never used
661: D401 First line should be imperative: 'return', not 'returns'
661: D400 First line should end with '.', not 'e'
661: D208 Docstring is over-indented
661: D200 One-line docstring should not occupy 3 lines
672: D401 First line should be imperative: 'return', not 'returns'
672: D400 First line should end with '.', not 'e'
672: D208 Docstring is over-indented
672: D200 One-line docstring should not occupy 3 lines
683: D103 Docstring missing
722: D103 Docstring missing
788: D103 Docstring missing
801: D290 White spaces around docstring should be trimmed.
801: D400 First line should end with '.', not 'a'
801: D205 Blank line missing between one-line summary and description
801: D208 Docstring is over-indented
841: D103 Docstring missing
956: D400 First line should end with '.', not 'd'
1011: D401 First line should be imperative: 'Harvest', not 'Harvests'
1011: D400 First line should end with '.', not 't'
1011: D208 Docstring is over-indented
1011: D200 One-line docstring should not occupy 3 lines
1023: D103 Docstring missing
1035: D401 First line should be imperative: 'Format', not 'Formats'
1035: D205 Blank line missing between one-line summary and description
1062: D400 First line should end with '.', not 't'
1072:15: E711 comparison to None should be 'if cond is None:'
1076:19: E711 comparison to None should be 'if cond is None:'
1092: D401 First line should be imperative: 'Launche', not 'Launches'
1092: D200 One-line docstring should not occupy 3 lines
1113: D400 First line should end with '.', not 'd'
1133: D400 First line should end with '.', not 'w'
1143: D103 Docstring missing
1151: D103 Docstring missing
1174: D290 White spaces around docstring should be trimmed.
1174: D400 First line should end with '.', not 'd'
1240: D103 Docstring missing
1284: D103 Docstring missing
1335: D103 Docstring missing
1341: D103 Docstring missing
1350: D103 Docstring missing
1369: D103 Docstring missing
1378: D103 Docstring missing
1389: D103 Docstring missing
1400: D103 Docstring missing
1407: D103 Docstring missing
1411: D103 Docstring missing
1417: D208 Docstring is over-indented
1463: D202 No blank lines allowed *after* function docstring, found 1
1542: D401 First line should be imperative: 'Find', not 'Finds'