[Store] Use MainActomaton

[inamiy]

Successor of:

• Introduce MainActomaton #64

Overview

This PR replaces Store's usage of actor Actomaton with @MainActor class MainActomaton which is introduced in #64 for:

1. Simplifying APIs, removing [Store] Add StoreConfiguration #40 StoreConfiguration
2. Enhanced state updates to be applied to SwiftUI views
   • Existing approach using non-main-thread actor Actomaton may sometimes cause old state updates when:
     1. setting StoreConfiguration.updatesStateImmediately = true and
     2. state updates occur in high frequency.

Issue 2b. has been observed when performing Actomaton-Gallery's LineCollisionExample which runs in 60 frames per seconds (by timer) + additional user-object-dragging, that led to too high update frequency.
While Store could update states on main-thread immediately by updatesStateImmediately = true, non-main-thread Actomaton may send older state back to Store due to slow operation, so this caused the malformed state update onto UI.