Standardize the DNS service we use for the JupyterBook team

[choldgraf]

Currently we have DNS entries split across two spaces:

• NameCheap (jupyterbook.org and a few others)
• Squarespace (mystmd.org and a few others)¹
• The moldovan government (for myst.md)
• And whatever the Jupyter project uses (if it has strong opinions about this, I'm not sure).

We should just pick one

We should just pick one service and standardize on it so that our URL domains aren't split across multiple providers.

Footnotes

1. Worth noting is that squarespace was recently purchased by a private equity firm. ↩

[rowanc1]

I would be up for standardizing on namecheap. Will take a tiny bit to move DNS over once we switch, but shouldn't be hard.