Add `RiskAssessment.template_id` column

* Foreign-key to Template
Merge remote-tracking branch 'origin/develop' into feature/add-risk-assessments-template-id
Add `RiskAssessmentControlMapping` model, table, endpoints

* Also removes 3 columns from RiskAssessmentMapping table
Fix migration to handle foreign key on `control_id`
Add display name for logs for RiskAssessentControlMapping
Merge pull request #916 from reciprocity/feature/add-risk-assessments-template-id

Add `RiskAssessment.template_id` column