custom field cursor pagination and field dynamic

[woylie]

• support cursor pagination on custom fields with field_dynamic
• pass runtime opts to build_op
• filter by custom fields with field dynamic (empty/not_empty)
• filter by custom fields with field dynamic (other operators)
• empty operators with field dynamic and array/map (requires casting)
• filter by field dynamic with arrays (requires casting)
• filter by field dynamic with binary IDs (requires casting)
• filter by field dynamic with like/starts_with/ends_with operators
• filter by field dynamic with contains/not_contains operator
• cast filter values when performing cursor pagination on custom fields
• update schema validation
• update docs

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Notes

• Using dynamic just for the field instead of the whole expression prevents automatic type casting.
• type/2 doesn't appear to support interpolation of the second argument (type(^value, ^ecto_type)