EC-4013 - Add "cacheMode" parameter properly

[radu-todirica]

Description

1. "cacheMode" field has been added to the createServiceOffering endpoint
2. "cacheMode" field will be returned in the listApis response for both createDiskOffering and createServiceOffering endpoints.
3. "cacheMode" field will be returned in the listServiceOfferings and listDiskOfferings endpoints.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)

Screenshots (if appropriate):

How Has This Been Tested?