environment configuration feature breaks @types/node

[macklus]

Short description of the problem:

Install @types/parse (who install @types/node) on ionic project, breaks beacuse src/declarations.d.ts also declare var process

What behavior are you expecting?

It should be compatible

Steps to reproduce:
1.ionic start
2.npm i @types/parse
3.create src/declarations.d.ts as explain on #1471
4.ionic serve

Error message was attached:

Which @ionic/app-scripts version are you using? 3.2.0

Other information: (e.g. stacktraces, related issues, suggestions how to fix, stackoverflow links, forum links, etc)