fix(build): pass team,site, addons env variables to build command

[erezrokah]

- Summary

Fixes #1331

- Test plan

Tested manually with the flow in https://github.com/nimbella/netlify-plugin-nimbella

- Description for the changelog

Inject relevant env variables when running the build command.

- A picture of a cute animal (not mandatory but encouraged)

[erezrokah]

@ehmicky since @netlify/config already evaluates some of these, should we move this logic to @netlify/config?

[ehmicky]

Yes.
I have filed netlify/build#2036 with additional information. However, this can be done in a follow-up PR.

[erezrokah]

Checking why this is failing on node 8

[erezrokah]

Looks like this is another issue with oclif. Some of the oclif packages we are using are referencing fs-extra@^9 which only supports node 10.

├─┬ @oclif/errors@1.3.3
│ └── fs-extra@9.0.1 
├─┬ @oclif/plugin-not-found@1.2.4
│ └─┬ cli-ux@4.9.3
│   └── fs-extra@7.0.1 
├─┬ @oclif/plugin-plugins@1.9.1
│ └── fs-extra@9.0.1  deduped
└─┬ cli-ux@5.5.0
  └── fs-extra@9.0.1  deduped

For example https://github.com/oclif/errors/blob/2233a100fbb8822a15a74e97c5f1ebd32c876a99/package.json#L35. A breaking change was done in https://github.com/oclif/errors/pull/27/files#diff-7ae45ad102eab3b6d7e7896acd08c427a9b25b346470d7bc6507b6481575d519R9, but was published as a minor version oclif/errors@v1.2.2...v1.3.0

Opened oclif/errors#97

[erezrokah]

@ehmicky this is ready for review

[ehmicky]

We should reach a conclusion in netlify/build#1514 before adding .env support in local builds. Would it be ok to split this specific feature from this PR?

[erezrokah]

Done in 1556c56

[ehmicky]

This is looking good.
Just one comment about .env files support.