mock-aws-s3, aws-sdk, nock dependencies vs devDependencies issue

Nobody has claimed this yet.

Usage of `mock-aws-s3`, `aws-sdk`, and `nock` are used in the call stack originating from `lib/node-pre-gyp.js` (which is the package `main`), but they are only listed in `"devDependencies"`.

```
"aws-sdk": "^2.1012.0",
"mock-aws-s3": "^4.0.2",
"nock": "^13.1.4",
```

This causes a problem with webpack:

```
ERROR in ../project/node_modules/@mapbox/node-pre-gyp/lib/util/s3_setup.js 43:20-42
Module not found: Error: Can't resolve 'mock-aws-s3' in '/Path/to/project/node_modules/@mapbox/node-pre-gyp/lib/util'
@ ../project/node_modules/@mapbox/node-pre-gyp/lib/node-pre-gyp.js 15:21-62
@ ../project/node_modules/bcrypt/bcrypt.js 3:17-48
@ ./src/lib/server/initialize.ts 3:0-69 9:12-39 21:23-56
@ ./src/index.ts 12:0-53 51:4-19

ERROR in ../project/node_modules/@mapbox/node-pre-gyp/lib/util/s3_setup.js 76:14-32
Module not found: Error: Can't resolve 'aws-sdk' in '/Path/to/project/node_modules/@mapbox/node-pre-gyp/lib/util'
@ ../project/node_modules/@mapbox/node-pre-gyp/lib/node-pre-gyp.js 15:21-62
@ ../project/node_modules/bcrypt/bcrypt.js 3:17-48
@ ./src/lib/server/initialize.ts 3:0-69 9:12-39 21:23-56
@ ./src/index.ts 12:0-53 51:4-19

ERROR in ../project/node_modules/@mapbox/node-pre-gyp/lib/util/s3_setup.js 112:15-30
Module not found: Error: Can't resolve 'nock' in '/Path/to/project/node_modules/@mapbox/node-pre-gyp/lib/util'
@ ../project/node_modules/@mapbox/node-pre-gyp/lib/node-pre-gyp.js 15:21-62
@ ../project/node_modules/bcrypt/bcrypt.js 3:17-48
@ ./src/lib/server/initialize.ts 3:0-69 9:12-39 21:23-56
@ ./src/index.ts 12:0-53 51:4-19
```

Either those modules should be moved to `"dependencies"`, or the main call chain should never hit them.

Inspect the dependency declarations and the call chain from lib/node-pre-gyp.js into lib/util/s3_setup.js. Reproduce the reported webpack resolution errors and determine whether the modules should be runtime dependencies or the call chain should avoid them. Done means the affected webpack build resolves successfully without introducing an invalid dependency classification.

Written by the indexing model from the issue text.