feat: Login via CLI (#298)

Fixes #210 - this isPR implements `coder login` in the case where the default user is already created.

This change adds:
- A prompt in the case where there is not an initial user that opens the server URL + requests a session token
  - This ports over some code from v1 for the `openURL` and `isWSL` functions to support opening the browser
- A `/api/v2/api-keys` endpoint that can be `POST`'d to in order to request a new api key for a user
  - This route was inspired by the v1 functionality
- A `cli-auth` route + page that shows the generated api key
- Tests for the new code + storybook for the new UI

The `/cli-auth` route, like in v1, is very minimal:

<img width="624" alt="Screen Shot 2022-02-16 at 5 05 07 PM" src="https://user-images.githubusercontent.com/88213859/154384627-78ab9841-27bf-490f-9bbe-23f8173c9e97.png">

And the terminal UX looks like this:

![2022-02-16 17 13 29](https://user-images.githubusercontent.com/88213859/154385225-509c78d7-840c-4cab-8f1e-074fede8f97e.gif)

codersdk/users.go

@@ -56,6 +56,20 @@ func (c *Client) CreateUser(ctx context.Context, req coderd.CreateUserRequest) (
 	return user, json.NewDecoder(res.Body).Decode(&user)
 }
 
+// CreateAPIKey calls the /api-key API
+func (c *Client) CreateAPIKey(ctx context.Context) (*coderd.GenerateAPIKeyResponse, error) {
+	res, err := c.request(ctx, http.MethodPost, "/api/v2/users/me/keys", nil)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	if res.StatusCode > http.StatusCreated {
+		return nil, readBodyAsError(res)
+	}
+	apiKey := &coderd.GenerateAPIKeyResponse{}
+	return apiKey, json.NewDecoder(res.Body).Decode(apiKey)
+}
+
 // LoginWithPassword creates a session token authenticating with an email and password.
 // Call `SetSessionToken()` to apply the newly acquired token to the client.
 func (c *Client) LoginWithPassword(ctx context.Context, req coderd.LoginWithPasswordRequest) (coderd.LoginWithPasswordResponse, error) {