Add alert message component and documentation

- Add custom alert component to simplify the use of custom alerts
- Add documentation for using the custom alert
- Update the login error alert to use the alert component instead of
the Bootstrap-vue component.
- Register alert component in enhanceApp
- Replace Sass variables used in the StatusIcon component style block
to use the Boostrap theme-color and gray Sass functions so the colors
can be used in the Vuepress documentation custom components

Signed-off-by: Derick Montague <derick.montague@ibm.com>
Change-Id: Ibd93402c919a42bd5c24cc9e7c6c8fc6f17a4db4
diff --git a/src/locales/en-US.json b/src/locales/en-US.json
index 1e676ee..63247da 100644
--- a/src/locales/en-US.json
+++ b/src/locales/en-US.json
@@ -134,8 +134,7 @@
     "password": "Password",
     "username": "Username",
     "alert": {
-      "title": "Invalid username or password",
-      "action": "Try again after verifying your username and password are correct."
+      "message": "Invalid username or password"
     }
   },
   "pageOverview": {