feat: improved api based on realtime-js (#14)

## Problem

The current Realtime Elixir library needed an API redesign to better
align with the
JavaScript implementation for consistency across Supabase ecosystems.
The existing
implementation had limitations in functionality and ergonomics compared
to the JS
version.

## Solution

The PR implements an improved API inspired by the realtime-js library,
including:
- Enhanced connection management with better state handling
- Expanded message handling and serialization
- More comprehensive channel registry functionality
- New behavior specifications for consistent implementation
- Additional utility functions matching the JS counterpart

## Rationale

By aligning the Elixir implementation with the JavaScript version, this
enhances
the developer experience for users familiar with the JS library. The
changes follow
Elixir best practices while maintaining API compatibility, making it
easier for
developers to work across languages in the Supabase ecosystem.

Author: zoedsoupe

.formatter.exs

@@ -1,4 +1,5 @@
 # Used by "mix format"
 [
+  plugins: [Styler],
   inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
 ]