Add new validate-dco and validate-gofmt bundlescripts for DCO and gofmt validation

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Remove the old Travis-specific files that are no longer necessary

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Change version to v0.10.0

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Merge pull request #5101 from unclejack/merge_release_v0.10.0

Merge release v0.10.0
Make remote API unit tests easier to read and write

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Merge pull request #5022 from tianon/make-validate

Add "make validate" for both local and CI gofmt and DCO verification
Update dns and volumes-from docs
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #5104 from crosbymichael/update-dns-vf-docs

Update dns and volumes-from docs
Merge pull request #5102 from shykes/api-cleanup-tests

Make remote API unit tests easier to read and write