Clean up of old node data directories

[kucharskim]

Could node cli on upgrade clean up data, which is known to be deprecated for long time. We have node machines which are pretty old. We see on some of them mysql-data but these days there is no MySQL / MariaDB databases running on SKALE nodes, as far as I can see. This is request is from the point of view of skale backups which we see are bigger on older machines, which contain data which we are pretty confident are unused today.

I can send you privately example list of directories from our nodes if you would like real life examples, what is on our nodes.

[kucharskim]

Backup sizes are below 10MB versus above 70MB between the nodes.

[dmytrotkk]

@kucharskim great point, we're actually going to work on the migration command to update SKALE nodes to the "post-FAIR" versions of SKALE Node where a lot of old stuff is removed/renamed/deprecated (for example, sqlite db is also removed in those versions) - I'll include mysql cleanup in the command too.

let me know if there is anything else we should keep in mind.

slightly off topic - we moved to the slim versions of base images for most of the containers on the node + optimized the build process, so the new images will be way smaller:

• CURRENT ADMIN: 1.25GB → NEW ADMIN: 339MB → -73%
• CURRENT TM: 1.12GB → NEW TM: 247MB → -77%
• CURRENT WATCHDOG: 1.21GB → NEW WATCHDOG: 186MB → -84%

that should help with root disk usage a bit.