refactor: introduce @bitwarden/state and other common libs (#15772)

* refactor: introduce @bitwarden/serialization

* refactor: introduce @bitwarden/guid

* refactor: introduce @bitwaren/client-type

* refactor: introduce @bitwarden/core-test-utils

* refactor: introduce @bitwarden/state and @bitwarden/state-test-utils

Creates initial project structure for centralized application state management. Part of modularization effort to extract state code from common.

* Added state provider documentation to README.

* Changed callouts to Github format.

* Fixed linting on file name.

* Forced git to accept rename

---------

Co-authored-by: Todd Martin <tmartin@bitwarden.com>

libs/state/src/core/user-state.provider.ts

@@ -0,0 +1,35 @@
+import { Observable } from "rxjs";
+
+import { UserId } from "@bitwarden/user-core";
+
+import { UserKeyDefinition } from "./user-key-definition";
+import { ActiveUserState, SingleUserState } from "./user-state";
+
+/** A provider for getting an implementation of state scoped to a given key and userId */
+export abstract class SingleUserStateProvider {
+  /**
+   * Gets a {@link SingleUserState} scoped to the given {@link UserKeyDefinition} and {@link UserId}
+   *
+   * @param userId - The {@link UserId} for which you want the user state for.
+   * @param userKeyDefinition - The {@link UserKeyDefinition} for which you want the user state for.
+   */
+  abstract get<T>(userId: UserId, userKeyDefinition: UserKeyDefinition<T>): SingleUserState<T>;
+}
+
+/** A provider for getting an implementation of state scoped to a given key, but always pointing
+ * to the currently active user
+ */
+export abstract class ActiveUserStateProvider {
+  /**
+   * Convenience re-emission of active user ID from {@link AccountService.activeAccount$}
+   */
+  abstract activeUserId$: Observable<UserId | undefined>;
+
+  /**
+   * Gets a {@link ActiveUserState} scoped to the given {@link KeyDefinition}, but updates when active user changes such
+   * that the emitted values always represents the state for the currently active user.
+   *
+   * @param keyDefinition - The {@link UserKeyDefinition} for which you want the user state for.
+   */
+  abstract get<T>(userKeyDefinition: UserKeyDefinition<T>): ActiveUserState<T>;
+}