Fix Docker All-in-one image build

[nwmac]

This PR:

• Removes the old docker file from the all-in-one folder
• Updated the docs
• Updates the docker file to work with the permissions changes in the new back-end builder image
• Use build-cf target to build front-end, so that this will work on low-memory systems - it failed on my Mac, but worked on beefier Linux box - tuning down allowed it to build

[cfdreddbot]

Hey nwmac!

Thanks for submitting this pull request! I'm here to inform the recipients of the pull request that you and the commit authors have already signed the CLA.

[codecov]

Codecov Report

Merging #2552 into v2-master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           v2-master    #2552   +/-   ##
==========================================
  Coverage      70.42%   70.42%           
==========================================
  Files            594      594           
  Lines          25132    25132           
  Branches        5674     5674           
==========================================
  Hits           17698    17698           
  Misses          7434     7434

[irfanhabib]

Successfully builds now in Concourse and locally