Fix issues #1 #2 and display form errors
	modified:   AdminIncludes/module_configuration.html
	modified:   Controller/MaintenanceAdminController.php
	modified:   EventListener/MaintenanceListener.php
	modified:   Form/MaintenanceSettingsForm.php
	modified:   I18n/AdminIncludes/fr_FR.php
	modified:   I18n/fr_FR.php
	modified:   Maintenance.php
	modified:   README.md
	modified:   templates/frontOffice/default/maintenance.html
Define form label and constraints
	modified:   AdminIncludes/module_configuration.html
	modified:   Form/MaintenanceSettingsForm.php
	modified:   Maintenance.php
apply changes in translation
	modified:   I18n/AdminIncludes/fr_FR.php
add validate form only on POST request
	modified:   Config/routing.xml
	modified:   Controller/MaintenanceAdminController.php
Use better standarts to display the maintenance message
	modified:   Config/config.xml
	new file:   Controller/MaintenanceController.php
	modified:   EventListener/MaintenanceListener.php
	renamed:    templates/frontOffice/default/maintenance.html -> templates/frontOffice/module_maintenance/maintenance.html
Set author annotations
	modified:   Controller/MaintenanceAdminController.php
	modified:   EventListener/MaintenanceListener.php
	modified:   Form/MaintenanceSettingsForm.php
Add module activation check in listener
	modified:   EventListener/MaintenanceListener.php
Fix cs
	modified:   Controller/MaintenanceAdminController.php
	modified:   Controller/MaintenanceController.php
	modified:   EventListener/MaintenanceListener.php
	modified:   Maintenance.php
Merge pull request #3 from lovenunu/lovenunu-fix

Lovenunu fix