Providers and Injections should be by name or at least by Map<string,type> and not by a simple Array<type>

### Version info

**Angular:** 14.2

**Firebase:** 9.9.3

**AngularFire:** 7.4.1

**Other (e.g. Ionic/Cordova, Node, browser, operating system):** Irrelevant

### Expected behavior

Provide / Injection by name or Map where the string is the name to find easy and clean your angular firebase components or have a function to findByName(name: string).

I'm not talking only about Auth, I'm talking regarding all your types but I use Auth for the examples

``` typescript
@NgModule({
imports: [
provideFirebaseApp(() => initializeApp(config)), // default app
provideFirebaseApp(() => initializeApp(config2, 'app2')),
provideFirebaseApp(() => initializeApp(config3, 'app3')),
provideAuth(() => getAuth()), // from default app
provideAuth(() => getAuth(getApp('app2'))),
provideAuth(() => getAuth(getApp('app3'))),
],
})
```

One of the next options should be there to be use it easy:

**Option 1** - Could be work with your actual Array but I think that search this search byName in this array is dirty and I recommend to not reinvent the wheel and use a Map
``` typescript
constructor(
private authApp: Auth,
private authApp2: AuthInstances.getByName('app2'),
private authApp3: AuthInstances.getByName('app3'),
) { }
```

**Option 2** - Could be work with your actual Array but again I recommend to not reinvent the wheel and use a Map
``` typescript
constructor(private authInstances: AuthInstances) { }

doWithAuth(name: string) {
const auth = this.authInstances.getByName(name)
// the things that you want to do with your auth
}
```

**Other options** - Any idea that let you select your angular fire element more easy and clean that now.

### Actual behavior

Provide / Injection is a simple Array and does not have any method to select by name.

``` typescript
@NgModule({
imports: [
provideFirebaseApp(() => initializeApp(config)), // default app
provideFirebaseApp(() => initializeApp(config2, 'app2')),
provideFirebaseApp(() => initializeApp(config3, 'app3')),
provideAuth(() => getAuth()), // from default app
provideAuth(() => getAuth(getApp('app2'))),
provideAuth(() => getAuth(getApp('app3'))),
],
})
```

``` typescript
private authMap: Map;
constructor(private authInstances: AuthInstances) {
this.authInstances.forEach(auth => {
this.authMap.set(auth.name,auth);
});
}
```

### Feedback

I think that your Provide / Injection should work with maps or with something that can be select the future injection by name.

Another important thing, is that you must declare a default app, if not the AuthInstaces fail because default app is not initializate and then to find this default app is so ugly `name: "[DEFAULT]"`

To finish, you cannot import only one auth if your auth is not default, because you have a way to import default and to import an array with default and another auths. Is there a way to inject `auth: Auth` by name and avoid import all the array?

Issue post from discussion: _Originally posted by @todosybuenrollo in https://github.com/angular/angularfire/discussions/1026#discussioncomment-3613308_

首先跟踪 issue 中描述的 provideFirebaseApp、provideAuth 和 AuthInstances 入口点，包括默认 Firebase 应用和命名 Firebase 应用的解析方式。在决定采用命名注入还是基于 map 的 API 之前，先检查当前的注入行为以及相关测试（如果有）。完成标准是：消费者可以按名称选择非默认的 Auth 实例，而无需手动扫描数组，同时保留默认应用的行为。

由索引模型根据 Issue 内容生成。