Get contextMenus list for creating groups at different levels

Hi Keith,

Tasks update
- [x] Added new api to get contextMenus list for creating groups at different levels
- [ ] Create center and group is broken, in next commit I will fix it

/cc @johnw65
As of now GROUP_LEVEL table structure looks like below

```sql
CREATE TABLE `m_group_level` (
	`id` INT(11) NOT NULL AUTO_INCREMENT,
	`parent_id` INT(11) NULL DEFAULT NULL,
	`is_super_parent` TINYINT(1) NOT NULL,
	`level_name` VARCHAR(100) NOT NULL,
	`recursable` TINYINT(1) NOT NULL,
	`can_have_clients` TINYINT(1) NOT NULL,
	PRIMARY KEY (`id`),
	INDEX `Parent_levelId_reference` (`parent_id`),
	CONSTRAINT `Parent_levelId_reference` FOREIGN KEY (`parent_id`) REFERENCES `m_group_level` (`id`)
)
```
I did not intended add "is_super_parent" because it can be derived. I will keep this for time being and once my coding is completed. I would like to take your help to review and correct necessary changes. 

Now I understand when you say "I think the usefulness of the attributes will be easier to see once the code get written" :) 

Thanks
Nayan Ambali