Add gitleaks and shellcheck to pre-commit configuration

[antonwolfy]

The PR extends pre-commit hooks with gitleaks (a tool for detecting and preventing hardcoded secrets) and with shellcheck (a tool that gives warnings and suggestions for bash/sh shell scripts).
All detected issues were resolved.

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[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/index.html

[vtavana]

Thank you, @antonwolfy!