## 🚀 Feature Proposal

Add support for the WebAuthn Automation API, a standard WebDriver extension that allows developers to create virtual authenticators to test websites using WebAuthn.

https://w3c.github.io/webauthn/#sctn-automation

_note: the above link may not work until https://github.com/w3c/webauthn/pull/1340 is merged_

## Motivation

At the moment there is no practical way to write e2e tests for pages using WebAuthn. Since this is a standard WebDriver API, the cost of implementing a layer on java is low.

## Example

For a page like this

```html
<button id="signup">Sign up with webauthn</button>
<span id="result"></span>
```

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

A test could be written like so:

```java
// HasVirtualAuthenticator is an interface that augments a RemoteWebDriver.
HasVirtualAuthenticator virtualAuthenticatorManager = ((HasVirtualAuthenticator) driver);
VirtualAuthenticatorOptions options = new VirtualAuthenticatorOptions();
VirtualAuthenticator authenticator =
    virtualAuthenticatorManager.addVirtualAuthenticator(options);
driver.findElement(By.id("signup")).click();
WebElement result = driver.findElement(By.id("result"));
new WebDriverWait(driver, 60, 1000).until(
    driver -> !result.getText().equals(""));
assertThat(result.getText()).isEqualTo("Success!");
```

## Implementation

We can implement the AddVirtualAuthenticator and RemoveVirtualAuthenticator methods first since they're the most useful and follow up with the others in subsequent PRs.
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;