Split package.json in two

[watson]

Today a lot of the devDependencies are related to testing only and make a lot of noise in our package.json file. @Qard have suggested that it might make sense to make a separate package.json file for testing only.

Greenkeeper recently announced support for monorepos, which would mean that we can now make another package.json file inside the test directory and move the devDependencies used for testing to there and still rely on Greenkeeper to get notified when for instance a new version of "mysql" is released.

[Qard]

Oh, nice! Didn't know they were working on monorepo support. 🎉

[trentm]

Bump prio a little bit because the optics of the security warning on the module just for the "hapi" tests is a little poor.