daemon: use standardized docker registry API for `GetLatestImageTag`

[bobheadxi]

Also for GetLatestImageTag function ghcr.io has REST API (given you have an authorization PAT). See https://docs.docker.com/registry/spec/api/#listing-image-tags

Tried doing a curl:

curl \
-H "Authorization: Bearer $(echo $PAT | base64)" \
-H "Accept: application/vnd.docker.distribution.manifest.list.v2+json" \
https://ghcr.io/v2/ubclaunchpad/inertiad/tags/list

Originally posted by @cheukyin699 in #716 (comment)