Add CNAME

[ExE-Boss]

This adds the CNAME file and points it at xmlns.novaapi.net.

Until this is merged, the website at the current location will continue to have broken styles.

Requirements:

The following records set in the NOVA website DNS settings:

A	xmlns	192.30.252.153
A	xmlns	192.30.252.154

With GitHub Pages now supporting HTTPS for custom pages, this instead needs to be:

A	xmlns	185.199.108.153
A	xmlns	185.199.109.153
A	xmlns	185.199.110.153
A	xmlns	185.199.111.153

or

CNAME	xmlns	nova-team.github.io

This has to be done by @calclavia who has access to the NOVA website DNS settings (see NOVA-Team/NOVA-Monorepo#207 (comment)).

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Once the above requirements are met, this can be merged.

[ExE-Boss]

@calclavia no longer owns the novaapi.net domain ☹.