Improve buffer pools statistics and report

[pasis]

TODO Add ticket number.

Description

XLIO_PRINT_REPORT now prints all the buffer pools reports unconditionally and shows number of the expands. xlio_stats prints also "in use" buffers along with the free buffers. There total number of allocation buffers is "in use" + "free".

What

Improve buffer pools statistics and report.

Why ?

User experience and system observability improvements.

How ?

It is optional but for complex PRs please provide information about the design, architecture, approach, etc.

Change type

What kind of change does this PR introduce?

• [ ] Bugfix
• [x] Feature
• [ ] Code style update
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] CI related changes
• [ ] Documentation content changes
• [ ] Tests
• [ ] Other

Check list

• [ ] Code follows the style de facto guidelines of this project
• [ ] Comments have been inserted in hard to understand places
• [ ] Documentation has been updated (if necessary)
• [ ] Test has been added (if possible)