remove gravatar dependency (#470)

Co-authored-by: Samuel Kleist <v-sakle@microsoft.com>

src/dashboard/Elsa.Dashboard/Areas/Elsa/Views/Shared/UserMenuItems.cshtml

@@ -7,7 +7,6 @@
     <a class="nav-link pr-0" href="#" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
         <div class="media align-items-center">
             <span class="avatar avatar-sm rounded-circle">
-                @* <img gravatar-email="@email" gravatar-size="36" alt="My Gravatar" src=""/> *@
             </span>
             <div class="media-body ml-2 d-none d-lg-block">
                 <span class="mb-0 text-sm  font-weight-bold">@userName</span>

src/dashboard/Elsa.Dashboard/Areas/Elsa/Views/_ViewImports.cshtml

@@ -1,5 +1,3 @@
-@using GravatarHelper.Common
 @using Elsa.Dashboard.Areas.Elsa.ViewModels
-@addTagHelper *, GravatarHelper.AspNetCore
 @addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
 @addTagHelper *, Elsa.WorkflowDesigner

src/dashboard/Elsa.Dashboard/Elsa.Dashboard.csproj

@@ -30,10 +30,6 @@
         <FrameworkReference Include="Microsoft.AspNetCore.App" />
     </ItemGroup>
 
-    <ItemGroup>
-        <PackageReference Include="GravatarHelper.AspNetCore" Version="1.1.0" />
-    </ItemGroup>
-
     <ItemGroup>
         <ProjectReference Include="..\..\core\Elsa.Abstractions\Elsa.Abstractions.csproj" />
         <ProjectReference Include="..\..\core\Elsa.Core\Elsa.Core.csproj" />