* Remove use of simplejson throughout code base. Fixes#42761
* Address failing tests
* Remove simplejson from contrib and other outlying files
* Add changelog fragment for simplejson removal
* Add dynamic inventory script and config for Packet.net
* The script and config have been shamelessly cargo
culted from the `ec2.py` and `ec2.ini` dynamic inventory
script.
* This is an initial version and could very well be
enhanced and made better.
Examples:
`PACKET_NET_API_KEY=<MY_AUTH_TOKEN> --list` to get inventory for
all hosts in Packet.net in all projects (defaults to `--list`
if no argument provided).
`PACKET_NET_API_KEY=<MY_AUTH_TOKEN> --host HOST` to get variables
for a single host.
* improvements in Packet host dynamic inventory
