Executes custom steps in build engine. See also:
sfdk configfor configuring the build target andsfdk build-initfor initializing build tree. More information: https://github.com/sailfishos/sailfish-qtcreator/blob/master/share/qtcreator/sfdk/modules/20-building-mb2/doc/command.build-shell.adoc.
sfdk build-shell
sfdk build-shell {{command}}
sfdk build-shell --maintain