Merge ttcli and Spring Initializr

[tvogel8570]

I'm trying to integrate your book section 4.2.2.2 with an existing project that was created on Spring Initializr. It was quite tedious to merge the two. Not sure the best way to make this easier, perhaps a set of guidelines about what is created, what needs to be moved and what needs to be merged would be of assistance.

Nirvana would be the ttcli tool can be run in a directory with an existing Spring Boot project and "it just works"!