Data protection for user columns at rest (#2571)

* ServerProtectedData for user entity

* remove using statements

* formatting

* use data protection libs

* no async

* add data protection to ef user repo

* switch to `SetApplicationName` per ASPNET docs

* null checks

* cleanup

* value converter for EF

* new line at eof

* fix using

* remove folder ref

* restore ctor

* fix lint

* use global constant

* UseApplicationServiceProvider for integration tests

* implement constant for DatabaseFieldProtectedPrefix

* Fix EF IntegrationTest

* restore original values after protect and save

* lint fixes

* Use Constants

Co-authored-by: Justin Baur <19896123+justindbaur@users.noreply.github.com>

src/Infrastructure.EntityFramework/Converters/DataProtectionConverter.cs

@@ -0,0 +1,33 @@
+using Bit.Core;
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+namespace Bit.Infrastructure.EntityFramework.Converters;
+public class DataProtectionConverter : ValueConverter<string, string>
+{
+    public DataProtectionConverter(IDataProtector dataProtector) :
+        base(s => Protect(dataProtector, s), s => Unprotect(dataProtector, s))
+    { }
+
+    private static string Protect(IDataProtector dataProtector, string value)
+    {
+        if (value?.StartsWith(Constants.DatabaseFieldProtectedPrefix) ?? true)
+        {
+            return value;
+        }
+
+        return string.Concat(
+            Constants.DatabaseFieldProtectedPrefix, dataProtector.Protect(value));
+    }
+
+    private static string Unprotect(IDataProtector dataProtector, string value)
+    {
+        if (!value?.StartsWith(Constants.DatabaseFieldProtectedPrefix) ?? true)
+        {
+            return value;
+        }
+
+        return dataProtector.Unprotect(
+            value.Substring(Constants.DatabaseFieldProtectedPrefix.Length));
+    }
+}