## 🚀 Feature Proposal

#7753 added basic support for WebAuthn automation in the form of the `addVirtualAuthenticator` and `removeVirtualAuthenticator` methods. Implement the rest of the methods: `addCredential`, `getCredential`, `removeCredential`, `removeAllCredentials`, `setUserVerified`.

## Motivation

Support more WebAuthn use-cases, like logging in with a specific credential, handling user verification failures, and inspecting generated credentials.

## Example

For a page like this

```html
<button id="login">Log in with WebAuthn</button>
<span id="result"></span>
```

```javascript
document.getElmentById("login").addEventListener("click", () => {
  navigator.credentials.get({...}).then(assertion => {
    document.getElementById("result").innerText = "Success!";
  })
});
```

A test could be written like so:

```java
// Set up the virtual authenticator.
HasVirtualAuthenticator virtualAuthenticatorManager = ((HasVirtualAuthenticator) driver);
VirtualAuthenticatorOptions options = new VirtualAuthenticatorOptions();
VirtualAuthenticator authenticator =
    virtualAuthenticatorManager.addVirtualAuthenticator(options);

// New code: inject a credential into the authenticator.
// Without this API the developer would have to generate a credential through
// navigator.credentials.create({...}) on the javascript side and would have less
// control over the resulting PK.
Credential credential = Credential.createNonResidentCredential(...params);
virtualAuthenticatorManager.addCredential(authenticator, credential);

// Assert login successful:
driver.findElement(By.id("login")).click();
WebElement result = driver.findElement(By.id("result"));
new WebDriverWait(driver, 60, 1000).until(
    driver -> !result.getText().equals(""));
assertThat(result.getText()).isEqualTo("Success!");
```
@Override
      @SuppressWarnings({"unchecked"})
      public Dimension getSize() {
        Response response = execute(DriverCommand.GET_CURRENT_WINDOW_SIZE);
        Map<String, Object> rawSize = (Map<String, Object>) response.getValue();
        int width = ((Number) rawSize.get("width")).intValue();
        int height = ((Number) rawSize.get("height")).intValue();
        return new Dimension(width, height);
      }
      Map<String, Object> rawPoint;
      @Override
      @SuppressWarnings("unchecked")
      public Point getPosition() {
        Response response = execute(DriverCommand.GET_CURRENT_WINDOW_POSITION());
        rawPoint = (Map<String, Object>) response.getValue();
        int x = ((Number) rawPoint.get("x")).intValue();
        int y = ((Number) rawPoint.get("y")).intValue();
        return new Point(x, y);
      }
      @Override
      public void maximize() {
        execute(DriverCommand.MAXIMIZE_CURRENT_WINDOW);
      }
      @Override
      public void fullscreen() {
        execute(DriverCommand.FULLSCREEN_CURRENT_WINDOW);
      }
    }
  }
  private class RemoteNavigation implements Navigation {