Add in Optimistic Locking (X_TIMESTAMP) header handling to SugarBean Endpoints

[MichaelJ2324]

It would be nice to enable Optimistic Locking on a Model for some use cases.

For example, one might be able to easily enable it on a Module

$client = new SugarApi();
$account = $client->module('Accounts', '12345');
$account->enableOptimisticLocking();
$account->retrieve();

$account['account_type'] = 'Test';
//Retrieve would handle setting date_modified 
//Save would handle configuring Request with X_TIMESTAMP header with date_modified value on object
$account->save();