Setup CAMDAC library

[NMNS93]

Major updates:

• Setup as library for install from github with remotes or devtools
• Included test data and helper function to download and unpack pipeline files
• Converted wrapper to pipeline_tumor_normal function
• Updated README with new install instructions

For development, the tumor-normal pipeline can now be tested in ~25 mins with testthat::test_local().

[elarosecadieux]

Hi Nana, once you've addressed the above I will accept the pull request. Great job!