Extract DB utils from action package
Related tasks
Context
The actions package defined a number of utility functions to get and migrate a database for unit tests.
Change
This MR extracts the utility function from the actions package and into their own utils/db/gorm package so that the functions can be used by all packages in Cloudsim.
Other information
Future work: move this to the ign-go repository, as other projects would benefit from these functions as well.