Tracking for release 0.16.0

[kozabrada123]

Opening this pr to track the changes for the next stable release, 0.16.0

Todos

• merge #521
• fix #523

Changes

Major changes:

• Implement gateway options and z-lib-stream compression (#508)
• Countless types updates by @Quat3rnion:
  • Using and adding distinct types instead of primitives (#501, #503, #505, #507, #509)
  • Add sqlx derives and implementations (#501, #505)
  • Make a facade type for Shared to be used in non-client contexts (#501)
  • Add new schemas (#503, #509)
  • Add bitflags serialization derive (#505)
• Remove dependency on openssl in favor of rustls and webpki_roots (#522)

Minor changes:

• Add the repository field to chorus_macros' cargo.toml (#496)
• (Internal) Minor improvements to CI (#498)
• (Internal) Replace Observer and GatewayEvent with pubserve crate (#524)

Fixes:

• Fix login and register to only create one gateway connection (#495)
• Add custom deserializer for PermissionOverwriteType (#512)
• (Internal) Use a macro to derive WebSocketEvent (#490 and #486)
• (Internal) Move Shared<T> to types/mod.rs (#492)
• (Internal) Deduplicate code for voice gateway backends (#493)

• 514:

  • fix PATCH /users/@me - It incorrectly returned a required password error, even if the current password was set
  • fix GET /users/@me/guilds - It incorrectly sent body parameters instead of query ones
  • don't log debug! for every successful ratelimited request - use trace! so it's less spamy
  • update the max expected compression ratio (several times) from 20 to 200. let's hope that will be enough
  • fix deserialization errors relating to guild folders in user settings
  • fix a panic in SqlxBitFlags if there are extra flags. It now truncates them
  • update chorus_macros to 0.4.1 (due to the above fix)
  • log (trace!) event data if we fail to parse it or it's unrecognised, for debugging purposes
  • fix a deserialization error in the MessageACK event
  • fix public_flags in user objects not being PublicFlags bitflags