Nipun/ssv flag different validator dir

[fighting-dreamer]

Aim of the PR :

1. we are suppose to use "presign" dir in place of "validators"
2. wallet users validators dir, it should use the presign directory.

broadly, in this PR, I have changes the host directory to be "presign" directory and mounted for the "validators" path.
the rest of logic remain as it it.

changes :

1. update the flow that created these stader node related directory : install.sh
2. update the templates to add mounting for validators path

[batphonghan]

I don’t think we should change the logic of the validator keys directory, as it's easy to cause errors. The changes should only introduce the presign directory.

[fighting-dreamer]

I don’t think we should change the logic of the validator keys directory, as it's easy to cause errors. The changes should only introduce the presign directory.

@batphonghan can you share a scenario that might error out ?