inventory: move control to def.cf, add simple CMDB loading code

* move `inventory_control` to `def.cf` for easier configuration
* add code to copy `me.json` file from the policy hub or locally from `$(sys.inputdir)/me.json` to `$(sys.workdir)/cmdb/me.json`
* load `$(sys.workdir)/cmdb/me.json` and, if successful, create a variable for each key as returned by `getindices`