This completely reworks the sysinfo module to add support for aggregate functions, better support for working with individual devices, the ability to specify units, and some string formatting support.
Several new tokens have also been added, and performance should be marginally improved.
BREAKING CHANGE: Use of the `sys_info` module in your config will need to be updated to use the new token format. See the wiki page for more info.
This PR includes the necessary code changes, CI changes and documentation to generate and deploy a full JSON schema for each release and the master branch, which can be used within config files for autocomplete and type checking.
