Enhance Run a Mithril Signer node (SPO) guide

[jpraynaud]

Issue

In order to facilitate the on-boarding of the SPOs, we want to enhance the Run a Mithril Signer node (SPO) guide.

Add examples in Run a Mithril Signer node (SPO) guide

Following some feedback from SPOs as in this discord message who were having difficulties to setup the signer node, we need to add real life examples of all the commands that are now specified with generic variables. A tip box is probably a good option with the current setup for release-preprod.

Add mention about aggregator in Mithril Signer Deployment model info box

This mention needs to explain that in the current setup the SPO does not need to install an aggregator (ran by IOG), just a signer.

Add mention on how to see squid logs

Add a mention with tail /var/log/squid/access.log to see squid logs

Add a signer registration verification command line

In order to help SPO verify that their signer node is correctly configured, we can add a command line to check that a specific logs is found.

Add a signer signature verification command line

In order to help SPO verify that their signer node is correctly signing certificates, we can add a command to check that a their pool id is found in one of the latest certificates.

To do

• Add examples in the Run a Mithril Signer node (SPO) guide
• Add mention about aggregator in Mithril Signer Deployment model info box
• Add mention on how to see squid logs
• Add a signer registration verification command line
• Add a signer signature verification command line