services: use memorySwap to be consistent with the app memory UI

the memory limit sliders take the total memory (memory + swap).

src/views/app.html

@@ -544,7 +544,6 @@
                 <div class="form-group">
                   <label class="control-label" for="memoryLimit">Memory Limit <sup><a ng-href="{{ config.webServerOrigin }}/documentation/apps/#memory-limit" class="help" target="_blank"><i class="fa fa-question-circle"></i></a></sup> : <b>{{ resources.memoryLimit ? resources.memoryLimit / 1024 / 1024 + 'MB' : 'Default (256 MB)' }}</b></label>
                   <p>Cloudron allocates 50% of this value as RAM and 50% as swap.</p>
-                  <br/>
                   <div style="padding: 0 10px;">
                     <slider id="memoryLimit" ng-model="resources.memoryLimit" step="134217728" tooltip="hide" ticks="resources.memoryTicks" ticks-snap-bounds="67108864"></slider>
                   </div>