Improved X-Registry-Auth content instructions

Hi,

this is a small contribution to fix some slightly unprecise information about the `X-Registry-Auth` header required to pull from private registries through the remote API. After a lot of trial and I error I managed to find that the documentation indications had this issues:

* Apparently single quotes cannot be used and double quotes (regular JSON) is required.
* Also the `auth` key must be passed even if empty or a 403 will result.
* It was not clear what the `serveraddress` had to be.

I added some small clarifications for anyone taking a look at the docs to keep them from the problems I've encountered. Hope this is helpful.

Thanks to all the contributors for bringing so much awesomeness to the linux world. :)

Signed-off-by: David Pelaez Tamayo <hello@davidpelaez.me>
Update remote_api_client_libraries.md

Ordering all clients alphabetically, by language.
Including all available languages in `page_keywords`.

Signed-off-by: Abhinav Ajgonkar <abhinav316@gmail.com>
add the timeutils package

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
use custom marshalling for JSONLog

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Removed runconfig.ParseSubcommand

 Removed runconfig.ParseSubcommand, changed it to runconfig.Parse and editted related tests and modules

Signed-off-by: Oh Jinkyun <tintypemolly@gmail.com>
Merge pull request #8095 from jfrazelle/cp-parse-subcommand-rebase

Removed runconfig.ParseSubcommand
Merge pull request #8041 from unclejack/lower_allocations_broadcastwriter

lower the number of allocations in broadcastwriter
Add a new MAINTAINERS file for the builder.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Merge pull request #8097 from erikh/builder_maintainers

Add a new MAINTAINERS file for the builder.
Merge pull request #8025 from davidpelaez-forks/docs-fix

Improved X-Registry-Auth content instructions
Merge pull request #8081 from abh1nav/master

Update remote_api_client_libraries.md
Fix logDone message for TestCopySingleFileToExistDir

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Add Build prefix to Copy tests

Now we can do "-run TestBuild" to test all build-tests and "-run
TestBuildCopy" for test all copy-tests

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Merge pull request #8105 from LK4D4/build_test_little_fix

Little fixes in cli build tests
tarsum: allow for alternate block ciphers

Not breaking the default cipher and algorithm for calculating checksums,
but allow for using alternate block ciphers during the checksum
calculation.

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)