Add email and website format validation

Simple validation following the HTML5 standard for emails as we don't
expect POIs to have convoluted email addresses. Only checks the
`website` and `email` tags as these are what iD currently supports with
fields.

data/core.yaml

@@ -1406,6 +1406,15 @@ en:
         feature:
           message: '{feature} lists Google as a data source'
         reference: "Google products are proprietary and must not be used as references."
+    invalid_format:
+      title: Invalid Formatting
+      tip: Find features tagged with invalid value formatting
+      email:
+        message: '{feature} is tagged with an invalid email address'
+        reference: 'Email addresses must be of the form "local-part@domain".'
+      website:
+        message: '{feature} is tagged with an invalid website'
+        reference: 'Websites should start with a "http" or "https" scheme.'
     missing_role:
       title: Missing Roles
       message: "{member} has no role within {relation}"
@@ -1921,4 +1930,4 @@ en:
   wikidata:
     identifier: "Identifier"
     label: "Label"
-    description: "Description"
+    description: "Description"