Replace Bluebird with native promises and async/await

[richarddd]

Well, this a rather big one and should be done in steps and with caution, preferably one file at the time.

I have been working with the framework for some time now and when you start digging into the core there are a lot of "old-ways" of doing stuff.

Proposed solution:

I divided this task into thee different issues, which should be handled in order

1. (Configure all promise returning functions as async functions #8368) Configure all promise returning functions as async
2. (Refactor any (Bb)Promise[resolve, reject] constructs #8603) Refactor any (Bb)Promise[resolve, reject] constructs
3. (Refactor all BbPromise.x usage which doesn't have native counterparts #8369) Convert all functions that rely on non-standard BbPromise usage to async/await and native promise interface
4. (This issue):

• Remove BbPromise.config calls
• Replace all BbPromise occurrences with Promise

[medikoo]

@richarddd great thanks for putting light on that.

Use async/await to avoid promise hell

We're aware of that issue, and want to do that shift soon. Still it'll require drop of support for Node.js v6+, and that's technically breaking semver wise, so we hold it until v2.0.0 release.

Use native promises

This best if done with async/await (otherwise it's doubled effort)

Remove lodash

We can do that now. I would start by replacing those that can be easily fill in by native counterparts (as _.forEach, _.includes etc.). PR is welcome

[medikoo]

@richarddd I've updated this issue to be strictly about refactor to native promises and async/await, I've also outlined a proposal on how we can approach it

[muskeinsingh]

@medikoo if we have a breakdown on how we can approach it probably I can pitch in, if that's okay.

[medikoo]

@muskeinsingh it'll simply be about refactoring all files that use bluebird so they do not use it.

Still at this point we need to wait for release of v2 first (and realization of #7362). We can assume this task is blocked until then

[muskeinsingh]

@medikoo sure. I'll be waiting for an update on that!

[medikoo]

As we've dropped Node.js v6 dependency we can handle this now. I've split this into three issues. Please see updated top level description for details