Fix errors and slowness during grunt-sass install process

[nylen]

Fixes #1212 and in the process significantly improves the runtime and performance of vagrant up (a fresh install now runs about 10-15 minutes faster for me).

Removing the &> /dev/null from npm install grunt-sass reveals a pretty nasty issue. It starts like this:

==> default: > [email protected] install /usr/lib/node_modules/grunt-sass/node_modules/node-sass
==> default: > node scripts/install.js
==> default: Unable to save binary /usr/lib/node_modules/grunt-sass/node_modules/node-sass/vendor/l$
nux-x64-48 : { Error: EACCES: permission denied, mkdir '/usr/lib/node_modules/grunt-sass/node_modul$
s/node-sass/vendor'
==> default:     at Error (native)
==> default:     at Object.fs.mkdirSync (fs.js:923:18)
==> default:     at sync (/usr/lib/node_modules/grunt-sass/node_modules/mkdirp/index.js:71:13)
==> default:     at Function.sync (/usr/lib/node_modules/grunt-sass/node_modules/mkdirp/index.js:77$
24)
==> default:     at checkAndDownloadBinary (/usr/lib/node_modules/grunt-sass/node_modules/node-sass$
scripts/install.js:111:11)
==> default:     at Object.<anonymous> (/usr/lib/node_modules/grunt-sass/node_modules/node-sass/scr$
pts/install.js:154:1)
==> default:     at Module._compile (module.js:570:32)
==> default:     at Object.Module._extensions..js (module.js:579:10)
==> default:     at Module.load (module.js:487:32)
==> default:     at tryModuleLoad (module.js:446:12)
==> default:   errno: -13,
==> default:   code: 'EACCES',
==> default:   syscall: 'mkdir',
==> default:   path: '/usr/lib/node_modules/grunt-sass/node_modules/node-sass/vendor' }

then, node-gyp kicks in with its own errors:

==> default: ensuring nodedir is created
==> default:  /usr/lib/node_modules/grunt-sass/node_modules/node-sass/.node-gyp/6.11.2
==> default: gyp
==> default:  
==> default: WARN EACCES user "root" does not have permission to access the dev dir "/usr/lib/node_m
odules/grunt-sass/node_modules/node-sass/.node-gyp/6.11.2"
==> default: gyp WARN EACCES attempting to reinstall using temporary dev dir "/usr/lib/node_modules/
grunt-sass/node_modules/node-sass/.node-gyp"

This same error message repeats, quickly reaching millions of log lines, until node-gyp runs out of memory:

==> default: FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
==> default:  1: node::Abort() [node-gyp]
==> default:  2: 0x10aaf3c [node-gyp]
==> default:  3: v8::Utils::ReportApiFailure(char const*, char const*) [node-gyp]
==> default:  4: v8::internal::V8::FatalProcessOutOfMemory(char const*, bool) [node-gyp]
==> default:  5: v8::internal::Factory::NewUninitializedFixedArray(int) [node-gyp]
==> default:  6: 0xc4d7cc [node-gyp]
==> default:  7: 0xc4d9f6 [node-gyp]
==> default:  8: 0xc4dc7b [node-gyp]
==> default:  9: v8::internal::JSArray
==> default: ::SetLength(v8::internal::Handle<v8::internal::JSArray>, unsigned int) [node-gyp]
==> default: 10: v8::internal::ArrayConstructInitializeElements(v8::internal::Handle<v8::internal::J
SArray>, v8::internal::Arguments*) [node-gyp]
==> default: 11: 0xe6e3e3 [node-gyp]
==> default: 12: v8::internal::Runtime_ArrayConstructor(int, v8::internal::Object**, v8::internal::I
solate*) [node-gyp]

Then the installation continues. Currently, all of this is hidden from the user, but towards the end of this node-gyp process, it's not possible to vagrant ssh into the VM because free memory is so low.

The fix here is not particularly elegant, but it's the only thing I've found that works, and I think the current state of things is much worse. See npm/npm#3849 (comment) and npm/npm#601 for some background.

[LoreleiAurora]

Why is this submodule needed? https://github.com/Varying-Vagrant-Vagrants/VVV/pull/1246/files#diff-18f9510f7573a97689ece9769566d254

[LoreleiAurora]

Fixes #1212

[nylen]

I'm not sure how the submodule got included. Removed in cd9aca4.