Provider qa feedback (#1501)

* Title case buttons

* Throw if provider tries to add a non-business organization

* Allow only one admin OR owner roll in a free org per user

Boolean operators were not properly assocated
and ownership of an org was precluding confirmation into any other
organization

* Limit email length

* Require email domain with top level domain

* Do not allow email domains to end in invalid characters

* Fix free org tests

src/Core/Utilities/StrictEmailAddressAttribute.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel.DataAnnotations;
+using System.Text.RegularExpressions;
 using MimeKit;
 
 namespace Bit.Core.Utilities
@@ -25,7 +26,12 @@ namespace Bit.Core.Utilities
                     return false;
                 }
             }
-            catch (ParseException e)
+            catch (ParseException)
+            {
+                return false;
+            }
+
+            if (!Regex.IsMatch(emailAddress, @"@.+\.[A-Za-z0-9]+$"))
             {
                 return false;
             }