implement nullability check for Postgres as a query on pg_attribute
implement type name fetching for Postgres as part of `describe()`
add nullability for describe() to MySQL
improve errors with unknown result column type IDs in `query!()`
run cargo fmt and fix warnings
improve error when feature gates for chrono/uuid types is not turned on
workflows/rust: add step to UI-test missing optional features
improve error for unsupported/feature-gated input parameter types
fix `PgConnection::get_type_names()` for empty type IDs list
fix `tests::mysql::test_describe()` on MariaDB 10.4
copy-edit unsupported/feature-gated type errors in `query!()`
Postgres: fix SQL type of string array
closes#107closes#17
Co-Authored-By: Anthony Dodd <Dodd.AnthonyJosiah@gmail.com>