refactor(gateway)!: remove create_* set of functions

[vilgotf]

The create_* set of functions in the stream module have a severe quirk, they would not set a shared Queue (users can set one themselves so we can't override it).

This PR resolves this pain point by simply removing these functions, which is possible without loosing the TLS reuse optimization as Config implements Clone. Still, users must be guided to reuse their Config, which is why this PR also removes the Shard::new function, leaving only Shard::with_config which takes a Config, however, this naming scheme is unusual, so the Shard::with_config function was also renamed to Shard::new.

Todo

• Update all examples
• Update documentation
  • Provide migration examples from the old (0.14) ShardScheme variants—belongs in the migration guide instead
  • Document escape hatch of reusing the TLS session, but setting other different settings (such as token and Queue), through cloning an existing Config, passing that to ConfigBuilder::with_config and then building a new Config
• Remove the unused twilight-http gateway feature

[vilgotf]

I split this PR into multiple commits to ease discussions about whether some of them should be split out into separate PRs

[vilgotf]

Not happening