Add Step-02 example agent: add a shell execution tool

[denis-domanskii]

Motivation and Context

Second step of the code agent example.

Breaking Changes

---

Type of the changes

• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Tests improvement
• Refactoring

Checklist

• The pull request has a description of the proposed change
• I read the Contributing Guidelines before opening the pull request
• The pull request uses develop as the base branch
• Tests for the changes have been added
• All new and existing tests passed

Additional steps for pull requests adding a new feature

• An issue describing the proposed change exists
• The pull request includes a link to the issue
• The change was discussed and approved in the issue
• Docs have been added / updated

[github-actions]

Qodana for JVM

17382 new problems were found

Inspection name	Severity	Problems
Unused import directive	🔶 Warning	16213
Check Kotlin and Java source code coverage	🔶 Warning	1156
Missing KDoc for public API declaration	🔶 Warning	11
If-Null return/break/... foldable to '?:'	◽️ Notice	2

@@ Code coverage @@
+ 70% total lines covered
15238 lines analyzed, 10796 lines covered
# Calculated according to the filters of your coverage tool

☁️ View the detailed Qodana report

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