revive this project and move to equinix-labs

[t0mk]

Revive this project for addition in Equinix Labs (github.com/equinix-labs)

• replace packngo with equinixgo (looks like only Projects and Devices lists are in place)
• append UserAgent
• remove unused and govendor from Makefile
• move to equnix-labs org
• add a note in the README about how to convert
• ensure the README.md covers installation and usage within prometheus (screenshots will help)
• add a deploy.equinix.com/labs page about it

Some of the above steps could be covered by (untested):

git rm -rf vendor .circleci
find . | xargs -I '{}' sed -i \
  -e s/packethost/equinix-labs/g \
  -e s/prometheus-packet-sd/prometheus-metal-sd/g \
  -e s/packet/metal/g \
  -e s/PACKET/METAL/g \
  -e 's/Packet/Equinix Metal/g' {}\;
go mod edit -go=1.20
go mod tidy

[t0mk]

@displague
Actually, we could do better - service discovery prometheus takes sd functionality in, into
https://github.com/prometheus/prometheus/tree/main/discovery

Linode use case:
prometheus/prometheus#8846

The service discovery components looks quite simple - it's code that lists compute resources and exports list with defined parameters to prometheus struct.

I asked in prometheus-dev slack if there's interest.