Update time-to-merge Service to Accept Raw Data as Input

[chauhankaranraj]

Currently the deployed service (#348) takes feature engineered PR data as input, and yields the estimated time to merge of the PR as output. However, if this service is to be used by thoth / openshift-ci / other github bots, then it would probably only have the raw PR data (such as that collected via mi-scheduler) available. And therefore, it won't be able to yield any meaningful output.

One idea to remedy this issue is to update the deployed Pipeline object in the service to include feature engineering objects as well.

Related to #236, #362

Acceptance Criteria

• feature engineering steps added to pipeline in deployed service

[chauhankaranraj]

/assign @chauhankaranraj @oindrillac