
Adds swift and file support for `redfish` management interface `firmware_update` step. Adds `source` to step and `[redfish]firmware_source` to config for setting up if and how files are staged. Support `http`, `local` and `swift` for staging. Adds `checksum` to step for checksum verification when file is staged. Story: 2008723 Task: 42067 Change-Id: Ibcc7815b32344d67f912d7dcda7283bac3582316