nginx/selfsign: non-standard RSA key size used

[alxndrsn]

At

central/files/nginx/setup-odk.sh

Line 33 in affc001

openssl req -x509 -newkey rsa:4086 \

, key size is set to 4086 bytes. Normal would be 4096.

It looks like this was copied from https://github.com/MarvAmBass/docker-nginx-ssl-secure/, which was the original base image used for nginx in this repo (marvambass/nginx-ssl-secure) in 7cd48f7.

There are unlikely to be advantages to using a marginally smaller key, but it might confuse some tooling.

Fixed upstream, per MarvAmBass/docker-nginx-ssl-secure#8.

[alxndrsn]

Closed by #2035