Refactor: Testable Keychain and Identity Manager (#584)

* Make static functions instance functions to be testable

* Injectable KeychainManager + Mock + updated tests

* Remove `pendingActions` from identity manager (dead code)

* Remove `getHandshakeState` from identity manager (dead code)

* Remove `getAllSocialIdentities` from identity manager (dead code)

* Remove `getCryptographicIdentity` from identity manager (dead code)

* Remove `resolveIdentity` from identity manager (dead code)

* Identity Manager: minor clean up

* Put Identity Manager behind a protocol

* Remove Keychain and Identity Manager singletons

* Tests: include MockKeychain/MockIdentityManager in project; init identityManager in CommandProcessorTests

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Co-authored-by: jack <jackjackbits@users.noreply.github.com>

bitchatTests/Mocks/MockKeychain.swift

@@ -0,0 +1,46 @@
+//
+// MockKeychain.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+@testable import bitchat
+
+final class MockKeychain: KeychainManagerProtocol {
+    private var storage: [String: Data] = [:]
+    
+    func saveIdentityKey(_ keyData: Data, forKey key: String) -> Bool {
+        storage[key] = keyData
+        return true
+    }
+    
+    func getIdentityKey(forKey key: String) -> Data? {
+        storage[key]
+    }
+    
+    func deleteIdentityKey(forKey key: String) -> Bool {
+        storage.removeValue(forKey: key)
+        return true
+    }
+    
+    func deleteAllKeychainData() -> Bool {
+        storage.removeAll()
+        return true
+    }
+    
+    func secureClear(_ data: inout Data) {
+        //
+        data = Data()
+    }
+    
+    func secureClear(_ string: inout String) {
+        string = ""
+    }
+    
+    func verifyIdentityKeyExists() -> Bool {
+        storage["identity_noiseStaticKey"] != nil
+    }
+}