Better copy/paste support for `exp caches`

Right now the caches printed are file paths:

block: `pre_training'
  algorithm: `test/iris_preprocessor/1'
  output: `/home/jae/code/beat.editor/prefix/cache/a9/e2/0b/2ba5928422351e52a508bd0cbc55e3d0e5bacb05896dc28413bcd0a1a4'
block: `pre_testing'
  algorithm: `test/iris_preprocessor/1'
  output: `/home/jae/code/beat.editor/prefix/cache/1e/a5/74/80c7d48bae3d0f6baf0883c3a7f78b5324830931029fcee4fd3bffff4d'
block: `training_alg'
  algorithm: `test/iris_training/1'
  output: `/home/jae/code/beat.editor/prefix/cache/45/61/15/3438e272598bf15e6bd729709536f4ca38b2b9d1061dd286c6dae5f288'
block: `testing_alg'
  algorithm: `test/iris_testing/1'
  output: `/home/jae/code/beat.editor/prefix/cache/39/d4/20/a6709aca3cac7e9a9a7cb2c36d536184554b5e19358927f2e866ad5751'
block: `analyzer'
  analyzer: `test/iris_analyzer/1'
  output: `/home/jae/code/beat.editor/prefix/cache/f0/a0/86/a645856dcbee4edc2729fcc60554212ed5def33334670602be6086aafb'

But you only use path segments relative to the cache folder to operate on that cache:

$ beat ca view a9/e2/0b/2ba5928422351e52a508bd0cbc55e3d0e5bacb05896dc28413bcd0a1a4

It would make sense for exp caches to only print out this bit, not the absolute path.