Implement fault tolerant provision for CSOM

[SubPointSupport]

[DONE] M2 should support fault tolerant CSOM based provision.
[DONE] Enhance CSOM provision so that it will survive IISRESET on the SP2013 farms

[TODO] "The request uses too many resources." while provisioning publishing sites - https://social.msdn.microsoft.com/Forums/office/en-US/3a328eae-4f93-49b8-b824-aed42594e34f/csom-site-provisioning-error-the-request-uses-too-many-resources?forum=appsforsharepoint

Should be implemented as the following one:

if (ex.Message.Contains("The request uses too many resources"))

[TODO] Some random O365/SQL based exception:

if (ex.ToString().Contains("0x80131904"))

Here's an idea. We notice Office 365 sometimes is suffering from connection problems. Where in the route these come from, I don't know, but they're there. They result in exceptions like "The underlying connection was closed", you've probably seen them once or twice.

So let's make an optional parameter for the DeployModel methods which takes an int retryCount. Check for connectivity failures and when a fault was due to connection loss, retry for this number of times. When we reach the retrycount and the error persist, just throw it like it is now. The default settings should be 0 so there is no impact to existing software.

https://www.yammer.com/spmeta2feedback/#/Threads/show?threadId=549681365

[SubPointSupport]

implemented as ClientRuntimeContextServiceBase / DefaultClientRuntimeContextService services. Could be replaced with custom implementation as well.

[SubPointSupport]

Added DefaultClientRuntimeContextService tests under "Regression.Impl.ClientRuntimeContextServiceBase"

DefaultClientRuntimeContextService has CustomExecuteQueryHandler meant to be used for custom impl, also InternalExecuteQuery()/ExecuteQuery() methods can be owerwritten.

[SubPointSupport]

Reopened die to the following enhancements:
[TODO] Enhance CSOM provision so that it will survive IISRESET on the SP2013 farms

[SubPointSupport]

Re-opened on [TODO] "The request uses too many resources." while provisioning publishing sites - https://social.msdn.microsoft.com/Forums/office/en-US/3a328eae-4f93-49b8-b824-aed42594e34f/csom-site-provisioning-error-the-request-uses-too-many-resources?forum=appsforsharepoint

SPMeta2.Exceptions.SPMeta2ModelDeploymentException: There was an error while provisioning definition. Check ModelNode prop. ---> Microsoft.SharePoint.Client.ServerException: Provisioning did not succeed. Details: Failed to initialize some site properties for Web at Url: 'XXXX' OriginalException: The request uses too many resources. at Microsoft.SharePoint.Client.ClientRequest.ProcessResponseStream(Stream responseStream) at Microsoft.SharePoint.Client.ClientRequest.ProcessResponse() at