Add Makefile for common commands

[loujaybee]

In: #24

There are commands like java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb to run DynamoDB locally, however it'd be nice if there was a central collection of these commands, so that you don't have to log them in comments.

This issue is to add a Makefile with a few initial commands.

This could also have things like:

• makefile list-tools => List all installed tools in the devbox.

(I'm sure I could think of other useful things for future, too 😝)