Scalr focuses on guardrails that enable self-service that uses indentity and permissions to determine what a user can do, but approval processes are supported either through CMDB (see ServiceNow answer) or in the product: https://scalr-wiki.atlassian.net/wiki/x/BBMb This capability will be expanded upon this year.
Product :
Scalr, Enterprise/7.7.2, Current Production
Feature :
Approval workflow, Built-In Features, User Self-Service