Add support for migration .js files being ES modules (ESM)

[mo]

When "db-migrate create" is executed it created a new .js file that uses commonjs. However, my project uses ES modules (ESM) i.e. I have "type": "module" in my main package.json file. For this reason I'm interested in one of these two features:

• Command line switch that makes "db-migrate create" create a .cjs file instead of a .js file.
• Command line switch that makes "db-migrate create" output an ES module (ESM) with "import" instead of require etc.

[wzrdtales]

already fixed in #724 (you can use the current latest beta version without worrying)