## 🚀 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!");
```
return new CommandPayload(ADD_COOKIE, ImmutableMap.of("cookie", cookie));
  }
  String GET_ALL_COOKIES = "getCookies";
  String GET_COOKIE = "getCookie";
  String DELETE_COOKIE = "deleteCookie";
  static CommandPayload DELETE_COOKIE(String name) {
    return new CommandPayload(DELETE_COOKIE, ImmutableMap.of("name", name));
  }
  String DELETE_ALL_COOKIES = "deleteAllCookies";
  String FIND_ELEMENT = "findElement";
  static CommandPayload FIND_ELEMENT(String strategy, String value) {
    return new CommandPayload(FIND_ELEMENT, ImmutableMap.of("using", strategy, "value", value));
  }
  String FIND_ELEMENTS = "findElements";
  static CommandPayload FIND_ELEMENTS(String strategy, String value) {
    return new CommandPayload(FIND_ELEMENTS, ImmutableMap.of("using", strategy, "value", value));
  }
  String FIND_CHILD_ELEMENT = "findChildElement";
  static CommandPayload FIND_CHILD_ELEMENT(String id, String strategy, String value) {
    return new CommandPayload(FIND_CHILD_ELEMENT,
                              ImmutableMap.of("id", id, "using", strategy, "value", value));
  }
  String FIND_CHILD_ELEMENTS = "findChildElements";
  static CommandPayload FIND_CHILD_ELEMENTS(String id, String strategy, String value) {
    return new CommandPayload(FIND_CHILD_ELEMENTS,
                              ImmutableMap.of("id", id, "using", strategy, "value", value));
  }
  String CLEAR_ELEMENT = "clearElement";
  static CommandPayload CLEAR_ELEMENT(String id) {
    return new CommandPayload(CLEAR_ELEMENT, ImmutableMap.of("id", id));