alicevision is in contrib because it depends on geogram, which is also in
contrib.

Some files were stripped out from the orig tarball:

  - src/dependencies/MeshSDFilter: this has been packaged in Debian
  - src/dependencies/nanoflann: this has been packaged in Debian
  - src/aliceVision/sfmDataIO/compatibilityData: this is large, and not needed
  - .github: this is not needed

The bundled vlfeat library in src/nonFree/sift/ (called "vlsift" here) has been
retained, because it contains modifications not present in the upstream vlfeat.
Here this is shipped in the libalicevision-vlsift.so library
