This patch introduces a new category called "suite".
A suite is a collection of workloads.
Each workload in a SuiteResource has a tag that can be narrowed down
through the function with_input_group.
Also, the set of input groups can be seen through list_input_groups.
Added unit tests to test all functions of SuiteResource class.
Change-Id: Iddda5c898b32b7cd874987dbe694ac09aa231f08
Co-authored-by: Kunal Pai <kunpai@ucdavis.edu>