base: database create/drop for storage engines

* Adds registry for storage engines.

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addresses #2020
30: D400 First line should end with '.', not '`'
30: D200 One-line docstring should not occupy 3 lines
46: D400 First line should end with '.', not '`'
53: D400 First line should end with '.', not '`'
53: D200 One-line docstring should not occupy 2 lines
58: D400 First line should end with '.', not '`'
58: D200 One-line docstring should not occupy 2 lines
69: D400 First line should end with '.', not '`'
69: D200 One-line docstring should not occupy 2 lines
74: D400 First line should end with '.', not '`'
78: D400 First line should end with '.', not '`'
82: D400 First line should end with '.', not 'e'
82: D205 Blank line missing between one-line summary and description
90: D400 First line should end with '.', not 'e'
90: D205 Blank line missing between one-line summary and description
98: D400 First line should end with '.', not '`'
101:25: F821 undefined name 'six'
110: D400 First line should end with '.', not '`'
114: D400 First line should end with '.', not '`'