Inject pending tasks to context

[Josh-XT]

This pull request introduces new methods to handle task retrieval for agents and integrates these methods into the interaction formatting process. The most important changes include the addition of new methods in agixt/Agent.py, the integration of task retrieval in agixt/Interactions.py, and the removal of an outdated method in agixt/Task.py.

New Methods for Task Retrieval:

• agixt/Agent.py: Added get_conversation_tasks method to retrieve tasks related to a specific conversation and format them in markdown.
• agixt/Agent.py: Added get_all_pending_tasks method to retrieve all pending tasks for an agent.

Integration of Task Retrieval:

• agixt/Interactions.py: Modified format_prompt to include tasks related to the conversation in the context if available.

Removal of Outdated Method:

• agixt/Task.py: Removed the get_tasks_by_agent method which was previously used to retrieve tasks for a specific agent.