## 🚀 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!");
```
if (value == null) { 
      throw new NoSuchElementException(String.format("Cannot locate an element using %s=%s", by, using));
    }
    WebElement element;
    try {
      element = (WebElement) value;
    } catch (ClassCastException ex) {
      throw new WebDriverException("Returned value cannot be converted to WebElement: " + value, ex);
    }
    setFoundBy(this, element, by, using);
    return element;
  }
  protected void setFoundBy(SearchContext context, WebElement element, String by, String using) {
    if (element instanceof RemoteWebElement) {
      RemoteWebElement remoteElement = (RemoteWebElement) element;
      remoteElement.setFoundBy(context, by, using);
      remoteElement.setFileDetector(getFileDetector());
    }
  }
  @SuppressWarnings("unchecked")
  protected List<WebElement> findElements(String by, String using) {
    if (using == null) {
      throw new IllegalArgumentException("Cannot find elements when the selector is null.");
    }
    Response response = execute(DriverCommand.FIND_ELEMENTS(by, using));
    Object value = response.getValue();
    if (value == null) { 
      return Collections.emptyList();
    }
    List<WebElement> allElements;