Add --request-payer to transfer commands

[kyleknap]

This builds on this previous PR: #3016

Compared to the original PR, there was a lot more lines added. For the most part, the logic from the original PR stayed intact. Just I added a lot of functional tests for this as practically all API requests used in a command will require the request payer header or the command will fail, and so I wanted to be sure that I caught all of the different scenarios (good thing I did too because I found a bug in s3transfer as well related to this). I also tested it locally on a bucket enabled for requester pays using an account that does not own the bucket and it was working well there. For anyone following/reviewing this PR, feel free to try it out locally as well and that will help double check I did not miss anything.

Also, note tests won't pass until this PR gets merged from s3transfer: boto/s3transfer#103

[codecov-io]

Codecov Report

Merging #3147 into develop will increase coverage by 0.01%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop    #3147      +/-   ##
===========================================
+ Coverage    97.09%   97.11%   +0.01%     
===========================================
  Files          406      407       +1     
  Lines        33362    33515     +153     
===========================================
+ Hits         32394    32547     +153     
  Misses         968      968

Impacted Files	Coverage Δ
awscli/customizations/s3/subcommands.py	97.21% <100%> (+0.05%)	⬆️
tests/functional/s3/test_mv_command.py	100% <100%> (+2.17%)	⬆️
awscli/customizations/s3/filegenerator.py	98.91% <100%> (ø)	⬆️
tests/functional/s3/test_cp_command.py	100% <100%> (ø)	⬆️
awscli/customizations/s3/s3handler.py	97.8% <100%> (ø)	⬆️
tests/functional/s3/test_sync_command.py	100% <100%> (ø)	⬆️
tests/unit/customizations/s3/test_utils.py	99.58% <100%> (+0.05%)	⬆️
tests/functional/s3/test_rm_command.py	100% <100%> (ø)	⬆️
tests/functional/s3/__init__.py	100% <100%> (ø)
awscli/customizations/s3/utils.py	97.97% <100%> (+0.11%)	⬆️
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 017279e...fb231df. Read the comment docs.

[JordonPhillips]

Looks good. I played around a little bit with it and it seems to work.

[aquanyc]

@kyleknap

When do you think there will be a version we can pull for testing ?

[kyleknap]

@aquanyc It was recently released in version 1.14.42. So I would recommend upgrading to the latest version of the CLI to start using it.