Invoke generator programmatically.

[chakrit]

Is your feature request related to a problem? Please describe. The generator is only available to command line users. It'd be nice if it could be programmatically invoked as well for other CLI programs that work with the database.

I took a look at the code and there's not really a ton of things being done in /cmd/jet/main.go, just needs to move things around a little.

Describe the solution you'd like

• Code in cmd/jet/main.go refactored into a function that can be called from outside the lib with similar options to the CLI.

[chakrit]

Just saw this on the wiki https://github.com/go-jet/jet/wiki/Generator#generating-from-the-code so closing this, for now.