Add support for nested Maybe records

[csamak]

Required ToMaybe, ToAlias, ToAliasReference instances for SqlMaybes
Also, required implementation changes to the sqlSelectProcessRow for SqlMaybes

Before submitting your PR, check that you've:

• Bumped the version number.
• [N/A] Documented new APIs with Haddock markup.
• [N/A] Added @since declarations to the Haddock.
• Ran stylish-haskell and otherwise adhered to the style guide.

After submitting your PR:

• Update the Changelog.md file with a link to your PR.
• Check that CI passes (or if it fails, for reasons unrelated to your change, like CI timeouts).

[parsonsmatt]

Nicely done!