[failure-diagnosis enhancement]awe-server API can provide more info for workunit failure.

New API:

view awe-client error log related to the failed workunit
curl -X GET http://<awe_api_url>/work/<work_id>?report=worknotes

Following two are existing APIs:

view stdout of one workunit (need client side config: [Client] print_app_msg=True)
curl -X GET http://<awe_api_url>/work/<work_id>?report=stdout

view stderr of one workunit (need client side config: [Client] print_app_msg=True)
curl -X GET http://<awe_api_url>/work/<work_id>?report=stderr