Custom `arangors` implementation

Related arangors issues and pull requests:

• https://github.com/fMeow/arangors/pull/83
• https://github.com/fMeow/arangors/pull/81
• https://github.com/fMeow/arangors/issues/82

arangors has a lot of complex feature gates I simplified here: https://github.com/ManevilleF/arangors/tree/arangors_lite

This PR could bring:

• Better aragog feature gates for blocking and async code
• Good rustls implementation (!99 (merged) doesn't remove the openssl dependencies)

This is in icebox until the custom arangors is deployed.