[Feat] Develop ansible module for creating custom SLAs in nutanix database service (ERA)

[bhati-pradeep]

Requirements:

• [x] module for create, update and delete SLAs

Todo:

• [x] Client SDK, get_spec()
• [x] Ansible spec & spec validator
• [x] Unit test, sanity test
• [x] Integration test
• [x] Documentation
• [x] Examples

[bhati-pradeep]

Feature added in v1.8.0 release