Squashed 'external/workload-automation/' changes from c6d23ab01..0f2de5f95

0f2de5f95 util/exec_control: add once_per_attribute_value
51ffd60c0 instruments: add proc_stat
0a4164349 Merge pull request #1065 from setrofim/doc-fix
fe50d7585 fw/instrument: derive Instrument from TargetedPlugin
b93a8cbbd doc: fix Instrument documentation
79dec810f fw/plugin: move cleanup_assets to TargetedPlugin
44cead2f7 fw/workload: Prefix `TestPackages` with "test_"

git-subtree-dir: external/workload-automation
git-subtree-split: 0f2de5f951c26e9f9a4cfe9720ca97fd55bd9081