Add explorer service uptime/status to https://pdp.vxb.ai/

[jennijuju]

(original discussion

The explorer maintainer team should set up internal alerts and proactively notify users if the explorer is experiencing degraded service (like a status/health check in explorer). Ideally, there should also be an easy way for users to contact the team directly to report issues, this way, FilOz doesn’t have to be the go-between.

[rjan90]

Moving this to the pdp-explorer repo