Fs cloning api handler

[mpacer]

This adds the handler needed to get file system cloning to work.

I will create a separate PR just for adding the handler to the routes and testing the routes.

NB: This is a bit of a bigger PR, but I didn't want to submit a PR for functionality without tests for that functionality.

[codecov[bot]]

Codecov Report

Merging #163 into master will decrease coverage by 1.15%. The diff coverage is 66.66%.

@@           Coverage Diff            @@
##           master   #163      +/-   ##
========================================
- Coverage   81.15%    80%   -1.16%     
========================================
  Files          10     10              
  Lines         467    505      +38     
========================================
+ Hits          379    404      +25     
- Misses         88    101      +13

[codecov[bot]]

Codecov Report

Merging #163 into master will increase coverage by 1.41%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #163      +/-   ##
==========================================
+ Coverage   81.15%   82.57%   +1.41%     
==========================================
  Files          10       10              
  Lines         467      505      +38     
==========================================
+ Hits          379      417      +38     
  Misses         88       88