Extension: Schema

[jlhumber]

ref https://www.geopackage.org/spec131/index.html#extension_schema

general

• [x] gpkg_data_columns table
• [x] gpkg_data_column_constraints table
• [x] Extension Records
• [x] drop table / feature class - handle clean-up
• [x] add constraints property to base class
• [x] tests based on table of examples

helpers

• [x] handling for insert on gpkg_data_columns
• [x] Range Constraint + insert
• [x] Enumeration Constraint + insert
• [x] Glob Constraint + insert