Template combo fixes

* Add empty text as 'No template'
* Layout fixes

This commit fixes #389
Template combo minor fix

Empty text as `Default Template`.
FIX MapStore Issue 361. Now Import/Export tool works correctly in Chrome.
fixes #352 Now the GUI provides information with MessageBox if the selected layer aren't queriable
fixes #355 Translation for Spatial Selector and Spatial Selector Query form
Groups' right

* Edit groups' rights in the metadata editor for the maps.
* New plugins for map manager
 * UserGroupComboBox to show a simple user group combo box
 * Resource group permission grid and window that manage the permissions for an resource
* This commit fixes #397 issue
Minor fixes

* Include `everyone` group to allow public maps.
* Change security rule title and icon for rule edit.
Some fixes.

* Review UserGroupComboBox namespace
* Allow map permission edition for users
* Include some i18n
* Map grid rowexpander fix
Remove last comma
fixes #355 Update translations
Template grid improvement

* Move row expander/collapser to top bar
* It is configurable setting `expandCollapseOnTopBar: false` on MSMTemplateGridPanel
Minor fixes

* Review panel titles on user manager and template manager
* Review tooltips of these buttons
* Minor review on template panel field case
URL with template Id. Close #401.
Template Manager - Collapse mode option. Close #390.
Merge pull request #399 from mricca/mapstore_issue_364

Removed last comma in objects
The "blur" function wasn't causing any problem.
Merge pull request #393 from mricca/mapstore_issue361

FIX MapStore Issue 361. Now Import/Export tool works correctly in Chrome
Merge pull request #394 from mricca/mapstore_issue352

fixes #352 Now the GUI provides information with MessageBox if the selec...
Merge pull request #395 from mricca/mapstore_issue355

fixes #355 Translation for Spatial Selector and Spatial Selector Query f...
Category initializers for MapStore and MapManager

* mxp.plugins.CategoriesInitializer for MapManager
* gxp.plugins.CategoriesInitializer for MapStore

This plugins check if there are a list of categories in GeoStore and create if not present.

Wiki page here: https://github.com/geosolutions-it/MapStore/wiki/Categories-Initializer (for gxp)

Fixes #386.
Resource permission fix

Put `record.data.canWrite` to write permission (it was using canRead)