chore: upgrade graphql dependency to major 16

[capaj]

fixes #1100

All tests pass except this one

The only problem is that I cannot find the version of graphql-tools which had SchemaDirectiveVisitor, I have checked out the whole repo and greped it on older commits, like for example on f0cb92e1361d10294b12a20188c2e1d57b92a543 and it's not there.
So if anyone can help me find source code for SchemaDirectiveVisitor, I can publish it on npm as separate module and we can fix that last test.

[MichalLytek]

I appreciate your work but I already have almost working v16 upgrade on my own branch:
https://github.com/MichalLytek/type-graphql/tree/v16

I only haven't enough time to migrate directive tests to the new graphql tools because they now do not support transforming input values. I have to dig more or refactor the tests as I only care about AST, not about whole ecosystem flow.