[FEATURE] Improve agent/task templating with Jinja2

[devin-ai-integration]

[FEATURE] Improve agent/task templating with Jinja2

Description

This PR implements the feature request from issue #2650 to improve agent/task templating with more flexible templating options. It adds support for:

• Container types (List, Dict, Set)
• Standard objects (datetime, time)
• Custom objects
• Conditional and loop statements
• Filtering options

The implementation uses Jinja2 for templating while maintaining backward compatibility with the existing {var} syntax.

Changes

• Add new jinja_templating.py file with functions to convert and render templates
• Update string_utils.py to use Jinja2 templating while maintaining backward compatibility
• Update Task class to use the new templating methods
• Add comprehensive tests for the new functionality
• Add documentation with examples

Testing

• Added unit tests for the new templating functions
• Added integration tests for the Task and Agent classes
• Verified backward compatibility with existing templates
• Ran all existing tests to ensure nothing is broken

Related Issues

Fixes #2650

Link to Devin run

https://app.devin.ai/sessions/7801774af00441378d6665e30ecb3929

Requested by

Joe Moura (joao@crewai.com)

[devin-ai-integration]

🤖 Devin AI Engineer

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[fmatray]

The autodetection is not necessarily a good idea.
For example, what happen if we have and error like {variable}}. It won't be detected correctly.
Moreover, it's not a good idea to mix between different templating engines (crewAI and jinja2)

It's better to have a configuration to switch between "crewAI" and "Jinja2" templating for the whole project.