Refactor temporary files generated by backend

[johnthagen]

First steps on #789

Closes #788

Follow on to #791

• Upload temporary lift zip files to /tmp instead of .CombineFiles
• Store whether Lift has been imported into a Project independent of the precense of the temporary zip file (Backend should remove temporary files created during export and import #786 (comment))
• Fix test (also refactor Lift round trip test to be a little more idiomatic)
• Fix Cannot import Lift File if project already contains an entry with an audio file #788

Database migration steps:

1. Search .CombineFiles for project folders that contain Import/*.zip
   • For each project, set {"liftImported": true} for that Project ID in the database

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This change is 

[codecov-io]

Codecov Report

Merging #810 (100d5d9) into master (4bfc0ed) will increase coverage by 0.23%.
The diff coverage is 91.66%.

@@            Coverage Diff             @@
##           master     #810      +/-   ##
==========================================
+ Coverage   51.03%   51.26%   +0.23%     
==========================================
  Files         239      239              
  Lines        6480     6505      +25     
  Branches      420      420              
==========================================
+ Hits         3307     3335      +28     
+ Misses       2863     2860       -3     
  Partials      310      310              

Flag	Coverage Δ
backend	55.68% <91.66%> (+0.45%)	⬆️
frontend	47.03% <ø> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
Backend/Controllers/AudioController.cs	54.23% <ø> (ø)
Backend/Services/LiftApiServices.cs	94.60% <ø> (ø)
Backend/Services/ProjectApiServices.cs	0.00% <0.00%> (ø)
src/types/project.tsx	100.00% <ø> (ø)
Backend/Models/Project.cs	72.38% <80.00%> (+0.16%)	⬆️
Backend/Controllers/LiftController.cs	57.50% <94.44%> (-0.52%)	⬇️
Backend/Helper/FileUtilities.cs	78.08% <100.00%> (+15.58%)	⬆️

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[imnasnainaec]

Reviewed 4 of 6 files at r3, 2 of 3 files at r4.
Reviewable status: 4 of 9 files reviewed, all discussions resolved (waiting on @imnasnainaec)

[jasonleenaylor]

Reviewed 1 of 3 files at r4, 4 of 4 files at r5.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @johnthagen)

[imnasnainaec]

Holding off merging this into master until #815 is also ready to use.