refactor: update example

[oacdutra]

Description

This PR make some updates into example folder:

1. Update demo.sh file
2. Create a rust example (demo.rs)
3. Remove unsed mempool option

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 16.3%. Comparing base (2753822) to head (b59ad87).

Additional details and impacted files

@@          Coverage Diff           @@
##           master    #318   +/-   ##
======================================
  Coverage    16.3%   16.3%           
======================================
  Files          16      16           
  Lines        1661    1661           
======================================
  Hits          271     271           
  Misses       1390    1390           

Flag	Coverage Δ
rust	16.3% <ø> (ø)

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[dr-orlovsky]

Thabk you very much! Will be able to review this before the next week

[oacdutra]

Hi @dr-orlovsky

Could you check if the PR is okay?

Thanks