transitive dependency cleanup

[RBusarow]

Mostly following the recommendations of DAGP, these changes:

• explicitly declare dependencies upon the transitive dependencies from other dependencies
• remove unused dependencies
• switch implementation with api and vice versa where necessary
  • I ignored api dependencies which "should" be implementation anywhere there's a comment saying they should be api
  • I also just left things as api in the internal testing modules

The first commit just sorts all dependency declarations. See the second commit for the actual changes.

fixes #847