[Provider] Server entities and models (#1370)

* Mock out provider models and service

* Implement CreateAsync, CompleteSetupAsync, UpdateAsync, InviteUserAsync and ResendInvitesAsync

* Implement AcceptUserAsync and ConfirmUsersAsync

* Implement SaveUserAsync and DeleteUserAsync

* Add email templates

* Add admin operations for providers

* Fix mail template names

* Rename roles

* Verify provider has provideradmin

* Add self hosted check to admin controller

* Resolve review comments

* Update sql queries

* Change create provider to use email instead of userId

src/Core/Enums/Provider/ProviderOrganizationProviderUserType.cs

@@ -0,0 +1,8 @@
+namespace Bit.Core.Enums.Provider
+{
+    public enum ProviderOrganizationProviderUserType : byte
+    {
+        Administrator = 0,
+        ServiceAdmin = 1,
+    }
+}

src/Core/Enums/Provider/ProviderStatusType.cs

@@ -0,0 +1,8 @@
+namespace Bit.Core.Enums.Provider
+{
+    public enum ProviderStatusType : byte
+    {
+        Pending = 0,
+        Created = 1,
+    }
+}

src/Core/Enums/Provider/ProviderUserStatusType.cs

@@ -0,0 +1,9 @@
+namespace Bit.Core.Enums.Provider
+{
+    public enum ProviderUserStatusType : byte
+    {
+        Invited = 0,
+        Accepted = 1,
+        Confirmed = 2,
+    }
+}

src/Core/Enums/Provider/ProviderUserType.cs

@@ -0,0 +1,8 @@
+namespace Bit.Core.Enums.Provider
+{
+    public enum ProviderUserType : byte
+    {
+        ProviderAdmin = 0,
+        ServiceUser = 1,
+    }
+}