migration created via bootstrap needs to account for dash in content type id

[Nintendot]

If the content type id is in the form of foo-bar, the migration src created would have defined constants in the same fashion, i.e:
const foo-bar = migration.createContentType('foo-bar') which obviously isn't semantically correct

I blame Contentful since obviously they allow dashes in id even though their web UI says otherwise:

SS/case 1: special chars not allowed, and rightfully so, notice error message says only letters numbers and underscores allowed

SS/case 2: dashes are accepted

[AnnaLeheta]

I also had an issue with trying to bootstrap existing content types. The ones that had dashes in the id (for example sort-text)failed and it was't easy to debug why. The error looked like this: