Installer shouldn't override spectrum scale documented defaults

[janfrode]

Describe the bug

The installer sets default block size to 1 MB, and default mount point to /mnt/fsname. This is deviating from the spectrum scale documented defaults of 4 MB block size, and /gpfs/fsname as default mount points. The installer probably shouldn't be pushing for different settings than the core product, unless there's a specific reason for it.

Also, the use of /mnt it's a violation of the The Filesystem Hierarchy Standard which says:

3.12. /mnt : Mount point for a temporarily mounted filesystem

3.12.1. Purpose

This directory is provided so that the system administrator may temporarily mount a 
filesystem as needed. The content of this directory is a local issue and should not affect 
the manner in which any program is run.

This directory must not be used by installation programs: a suitable temporary directory 
not in use by the system must be used instead.