Remove global PROMISETIME, use GenericAgentConfig::policy_last_read_attempt
Reload policy files in daemon based on which files were parsed in previous load.
Factor out ReadPolicyValidatedFileMTime from GenericAgentIsPolicyReloadNeeded
Check access from source files in policy, rather than from InputFiles
Add inputs attribute to body file control

This lets you include files from other files, allowing for easier
maintenance of modular policies.