Refactor: Reduce reliance of the package on 3rd party dependencies

[TesteurManiak]

I'm seeing that this package has a lot of 3rd party dependencies that could be avoided. This is not good as some might conflict in projects that also depend on it (and it might also make the maintenance more cumbersome). This PR aims to reduce the number of dependencies to its bare minimum.

Removed dependencies

• collection -> implemented firstWhereOrNull locally
• equatable -> override equality operator and hashCode for the classes that needed it
• meta -> Refactored PhoenixSocketOptions so it can be made const
• pedantic -> Not needed and deprecated
• quiver -> Replaced ListMultimap<String, void Function(PushResponse)> with a Map<String, List<void Function(PushResponse)>>

I've also bumped the version of the dev dependencies and bumped the minimum version of the Dart SDK to 3.0.0 so pattern matching can be used.

[TesteurManiak]

I'm not sure if you should get rid of the collection package.

collection was only used for firstWhereOrNull, I don't really see the dependency should be kept for such a simple extension. 🤔