Use template args for the contract start and end date

pointing to base.ini in the JS file resulted in the raw string content of base.ini to be in the JS bundle

atst/routes/task_orders/new.py

@@ -7,6 +7,7 @@ from flask import (
     current_app as app,
     jsonify,
 )
+from datetime import datetime
 
 from . import task_orders_bp
 from atst.domain.authz.decorator import user_can_access_decorator as user_can
@@ -22,6 +23,9 @@ def render_task_orders_edit(
 ):
     render_args = extra_args or {}
 
+    render_args["contract_start"] = app.config.get("CONTRACT_START_DATE")
+    render_args["contract_end"] = app.config.get("CONTRACT_END_DATE")
+
     if task_order_id:
         task_order = TaskOrders.get(task_order_id)
         portfolio_id = task_order.portfolio_id