Add support for sqlx types

[patrickariel]

Description

Adds support for encoding and decoding to/from sqlx types. This is useful when you want to use this library's types for your database via sqlx.

The implementation is gated behind the optional sqlx feature, turned off by default. The additional sqlx_postgres feature can also be enabled, if the user wants to decode/encode arrays of email addresses for PostgreSQL databases.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• cargo test --all-features

Environment (please complete the following information):

• Platform: Linux
• Rust: rustc 1.84.0-nightly (a0d98ff0e 2024-10-31)
• Cargo: cargo 1.84.0-nightly (e75214ea4 2024-10-25)

Checklist:

• My code follows the style guidelines of this project (e.g. run cargo fmt)
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• My changes DO NOT require unstable features without prior agreement
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules