Feature/add min hops config

[i-hate-nicknames]

Did you run make format && make check?

Fixes #319

Changes:

• Add min_hops visor router config option

How to test this PR:

[Darkren]

Great job!

[jdknives]

@i-hate-nicknames since this is changing the config of a visor, we need to think about whether we need to add this to the config migration and whether we need to bump the config version.

[i-hate-nicknames]

@jdknives I'm not sure if migration is needed, and what is the procedure. I need to research it.

As of now, I can't think of issues that can be introduced by this change.

If new code reads old config format, the values are not there and config struct gets zero values. Zero value of minHops is the default value, so no problem there. Zero value of maxHops is a problem, but it is reset to default value (50) here for such case.

If old code reads new config file, the values will be ignored (no change in the structure is made, only new fields are added).