[Communication] - PhoneNumberClient - Adding LRO for purchasing phone (Azure#15803)

* Implement long running operatins

* Update readme with long running opertions

* Address review issues and rename search to reservation - WIP

* move operations to Model namespace
use lock
reorange operation classes

* remove unused terminalStatuses initialization

* use ReservationStatus type for PhoneNumberReservationPurchaseOperation

* use ReservationStatus type for PhoneNumberReservationPurchaseOperation - update readmy

* Merge branch 'master' into pavel/feature/communication/lro

* Merge branch 'master' into pavel/feature/communication/lro

* addressing PR feedback

* LRO - removed HasSucceeded and Error properties from operation

* LRO - removed HasSucceeded and Error properties from operation

* Administratin LRO addressing PR feedback

Author: pavelprystinka

sdk/communication/Azure.Communication.Administration/README.md

@@ -101,9 +101,9 @@ Phone plans come in two types; Geographic and Toll-Free. Geographic phone plans
 
 All geographic phone plans within the same country are grouped into a phone plan group with a Geographic phone number type. All Toll-Free phone plans within the same country are grouped into a phone plan group.
 
-### Searching and acquiring numbers
+### Reserving and acquiring numbers
 
-Phone numbers search can be performed through the search creation API by providing a phone plan id, an area code and quantity of phone numbers. The provided quantity of phone numbers will be reserved for ten minutes. This search of phone numbers can either be cancelled or purchased. If the search is cancelled, then the phone numbers will become available to others. If the search is purchased, then the phone numbers are acquired for the Azure resources.
+Phone numbers reservation can be performed through the reservation creation API by providing a phone plan id, an area code and quantity of phone numbers. The provided quantity of phone numbers will be reserved for ten minutes. This reservation of phone numbers can either be cancelled or purchased. If the reservation is cancelled, then the phone numbers will become available to others. If the reservation is purchased, then the phone numbers are acquired for the Azure resources.
 
 ### Configuring / Assigning numbers
 
@@ -190,19 +190,34 @@ foreach (var secondaryAreaCode in areaCodes.SecondaryAreaCodes)
 }
 ```
 
-### Create search
+### Create reservation
 
 ```C#
-var searchOptions = new CreateSearchOptions(displayName, description, plans, areaCode) { Quantity = 1 };
-var createSearchResponse = client.CreateSearch(searchOptions);
+var reservationOptions = new CreateReservationOptions(displayName, description, plans, areaCode) { Quantity = 1 };
+var reservationOperation = await client.StartReservationAsync(reservationOptions).ConfigureAwait(false);
+var reservationResponse = await reservationOperation.WaitForCompletionAsync().ConfigureAwait(false);
 
-Console.WriteLine($"Search result: SearchId: {createSearchResponse.Value.SearchId}");
+Console.WriteLine($"ReservationId: {reservationResponse.Value.ReservationId}, Status {reservationResponse.Value.Status}");
 ```
 
-### Purchase search
+### Purchase reservation
 
 ```C#
-client.PurchaseSearch(searchId);
+var reservationPurchaseOperation = await client.StartPurchaseReservationAsync(reservationId).ConfigureAwait(false);
+await reservationPurchaseOperation.WaitForCompletionAsync().ConfigureAwait(false);
+
+// Ensure purchase has completed successfuly
+try
+{
+    var reservationStatus = reservationPurchaseOperation.Value;
+    // ...
+}
+catch (Exception ex)
+{
+    Console.WriteLine("Purchase failed");
+    Console.WriteLine(ex.Message);
+}
+
 ```
 
 ### Configure phone number
@@ -213,6 +228,15 @@ var phoneNumber = new PhoneNumber("<phone_number>");
 client.ConfigureNumber(pstnConfiguration, phoneNumber);
 ```
 
+### Release phone numbers
+
+```C#
+var releasePhoneNumberOperation = await client.StartReleasePhoneNumbersAsync(numbers).ConfigureAwait(false);
+await releasePhoneNumberOperation.WaitForCompletionAsync().ConfigureAwait(false);
+
+Console.WriteLine($"ReleaseId: {releasePhoneNumberOperation.Value.ReleaseId}, Status: {releasePhoneNumberOperation.Value.Status}");
+```
+
 ## Next steps
 [Read more about Communication user access tokens][user_access_token]