feat: add customizable removal check for Request resource

[arielsepton]

Description: Customizable Removal Check for Request Resource

This PR introduces a new optional field, isRemovedCheck, for the Request resource. This enhancement allows users to define custom logic for determining if a resource is removed. The field supports two types:

1. DEFAULT: The resource is considered removed if the OBSERVE response has a 404 status code.
2. CUSTOM: Allows users to define JQ-based logic for evaluating the removal status.

Example:

For a CUSTOM check:

isRemovedCheck:
  type: CUSTOM
  logic: |
    if .response.statusCode == 404
      and .response.body.error == "User not found"
      then true 
      else false 
      end

Behavior:

• If the JQ query evaluates to false, a REMOVE request is triggered to delete the resource.
• If the query evaluates to true, the resource is considered deleted and no further action is taken.

This feature enhances flexibility by enabling fine-grained control over resource removal logic.

Changes:

• Updated the schema to include the isRemovedCheck field.
• Added validation and execution logic for the new field.
• Enhanced documentation for Request resource with examples of isRemovedCheck usage.

Testing:

• Unit tests added for both DEFAULT and CUSTOM scenarios.

Related Issues

Resolves: #67