Enhancement/kotlin/retrofit2

[ch4rl3x]

#5076

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PR Description

This PR add the option to use koltin suspend functions combined with retrofit2. Also adds more complexity (authorization) and ability to customization to the ApiClient.

@jimschubert @dr4ke616 @karismann @Zomzog @andrewemery @4brunu

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[ch4rl3x]

@4brunu you was right. I checked it again, was my fault. moshiBuilder/gsonBuilder as lazy is not neccessary. I changed it also back to val instead of var, like before

[4brunu]

The PR ir really big, and a bit difficult to review.
Would it be possible to split it into smaller parts?

[ch4rl3x]

Thats a good question. The kotlin-retrofit2 library was too simple. We tooked most parts from java-retrofit2. Because of that, its such a big PR

[4brunu]

I saw that you changed the path of all the sample projects, and I think that's whats causing some many files being changed.
Could you please submit that change in a different PR please?

[ch4rl3x]

Ok, so do i have to close these PR and create a clean, new one?

[4brunu]

No, you can keep this one open.
Just create a new one with the only the current sample projects being moved around.
When the new one get's merged, the diff in this PR vs the master branch will be much smaller.

[ch4rl3x]

@wing328 I will make a new/simpler PR without renaming etc

[wing328]

@ch4rl3x FYI. #5750 has been merged into master.

Shall we close this PR?

[ch4rl3x]

I will make a new PR within the next few weeks hopefully