tech(cleaning): Rename IdentityMap and remove Observer protocol (#61)

Author: pjechris

Sources/CohesionKit/Identity/AliasKey.swift renamed to Sources/CohesionKit/AliasKey.swift

@@ -1,7 +1,7 @@
 #if canImport(Combine)
 import Combine
 
-extension Observer {
+extension EntityObserver {
     /// A `Publisher` emitting the observer current value and subscribing to any subsequents new values
     public var asPublisher: AnyPublisher<T, Never> {
         let subject = CurrentValueSubject<T, Never>(value)

Sources/CohesionKit/Combine/EntityObserver+Publisher.swift

@@ -1,7 +1,7 @@
 import Foundation
 
 /// A type registering observers on a given entity from identity storage
-public struct EntityObserver<T>: Observer {
+public struct EntityObserver<T> {
     public typealias OnChange = (T) -> Void
 
     public let value: T

Sources/CohesionKit/Identity/IdentityStore.swift renamed to Sources/CohesionKit/EntityStore.swift

@@ -2,7 +2,7 @@ import XCTest
 @testable import CohesionKit
 
 // MARK: Store
-class IdentityMapTests: XCTestCase {
+class EntityStoreTests: XCTestCase {
     func test_storeAggregate_nestedEntitiesAreStored() {
         let entity = RootFixture(
             id: 1,
@@ -154,7 +154,7 @@ class IdentityMapTests: XCTestCase {
 }
 
 // MARK: Find
-extension IdentityMapTests {
+extension EntityStoreTests {
     func test_find_entityStored_noObserverAdded_returnNil() {
         let identityMap = IdentityMap()
         let entity = SingleNodeFixture(id: 1)
@@ -277,7 +277,7 @@ extension IdentityMapTests {
 
 // MARK: Update
 
-extension IdentityMapTests {
+extension EntityStoreTests {
 
     func test_update_entityIsAlreadyInserted_entityIsUpdated() {
         let identityMap = IdentityMap()