Replacing bae with darling

[billy1624]

Motivation

Currently, we depends on https://crates.io/crates/bae to parse the procedural macro attributes. However, it's no longer maintained and still depends on syn v1.

Proposed Solutions

We want to drop the use of https://crates.io/crates/bae and https://crates.io/crates/bae2 completely. And switch to https://crates.io/crates/darling instead.

[billy1624]

Demo PR

• Proc macro parsing with darling and test #1412
• POC: try darling #1560

[billy1624]

Don't try to rewrite all procedural macros and parse proc_macro attributes with darling.

Just focus on keeping the behaviour of proc_macro the same. While drop the use of bae, i.e. the line below

bae = { version = "1", package = "bae2", default-features = false, optional = true }

These three files should be changed