Fixes #983 - Prevent NPE when adding/update Pages and Structured Content when validating

(cherry picked from commit 258cca244a5f101e7c6920de758d06476dc9d7f5)

Conflicts:
	admin/broadleaf-open-admin-platform/src/main/java/org/broadleafcommerce/openadmin/server/service/persistence/validation/EntityValidatorService.java
	admin/broadleaf-open-admin-platform/src/main/java/org/broadleafcommerce/openadmin/server/service/persistence/validation/EntityValidatorServiceImpl.java
#986 - Provide locking for order operations

Cherry picked from (dbf2720d24c5ec5b9be7cd89935227a69c5b1eba)
#986 - Keep session locks in a separate map
#986 - Remove accidentally committed line
Merge branch 'BroadleafCommerce-3.0.x' into BroadleafCommerce-3.1.x

Conflicts:
	admin/broadleaf-open-admin-platform/src/main/java/org/broadleafcommerce/openadmin/server/service/persistence/validation/EntityValidatorService.java
	admin/broadleaf-open-admin-platform/src/main/java/org/broadleafcommerce/openadmin/server/service/persistence/validation/EntityValidatorServiceImpl.java
	core/broadleaf-framework-web/src/main/resources/bl-framework-web-applicationContext.xml
	core/broadleaf-framework/src/main/java/org/broadleafcommerce/core/order/service/OrderService.java
	core/broadleaf-framework/src/main/java/org/broadleafcommerce/core/order/service/OrderServiceImpl.java