Revamp support dump to be synchronous
Revamp support dump to be synchronous

It turns out that our support dump logic is *really* fast and compact.
Even on a large node (hundreds of containers and thousands of images)
it runs in ~10 seconds and weighs in at a few hundred K.  Since we're
running all the dumps in parallel, there's really no need for the added
complexity of saving them to a DB.

This change revamps and simplifies the support dump API.  Now you simply
POST to the API endpoint, and it will stream the full zip file containing
all the nodes payloads within.  If a node is unreachable, times out,
or has some other catastrophic problem, the contents for that node will
be an error message instead of the normal tar.gz bundle.

I've tested this with a swarm of multiple nodes, confirmed the dumps
match up to the hosts, and the system handles offline nodes, reporting
an error message within the bundle.  (it does take a long time in the
failure cases due to a bug in swarm that's slated to be fixed in 1.9,
but curl doesn't give up so this still works fine.)

denverdino/denverdino.github.io,johnstep/docker.github.io,BSWANG/denverdino.github.io,docker-zh/docker.github.io,anweiss/docker.github.io,phiroict/docker,thaJeztah/docker.github.io,shubheksha/docker.github.io,shubheksha/docker.github.io,johnstep/docker.github.io,jzwlqx/denverdino.github.io,joaofnfernandes/docker.github.io,aduermael/docker.github.io,shubheksha/docker.github.io,sanscontext/docker.github.io,anweiss/docker.github.io,gdevillele/docker.github.io,denverdino/docker.github.io,londoncalling/docker.github.io,alexisbellido/docker.github.io,alexisbellido/docker.github.io,denverdino/docker.github.io,LuisBosquez/docker.github.io,denverdino/docker.github.io,menglingwei/denverdino.github.io,menglingwei/denverdino.github.io,docker/docker.github.io,joaofnfernandes/docker.github.io,thaJeztah/docker.github.io,anweiss/docker.github.io,bdwill/docker.github.io,JimGalasyn/docker.github.io,aduermael/docker.github.io,denverdino/denverdino.github.io,shin-/docker.github.io,denverdino/denverdino.github.io,anweiss/docker.github.io,londoncalling/docker.github.io,docker/docker.github.io,alexisbellido/docker.github.io,menglingwei/denverdino.github.io,troy0820/docker.github.io,BSWANG/denverdino.github.io,JimGalasyn/docker.github.io,troy0820/docker.github.io,bdwill/docker.github.io,LuisBosquez/docker.github.io,LuisBosquez/docker.github.io,phiroict/docker,LuisBosquez/docker.github.io,sanscontext/docker.github.io,JimGalasyn/docker.github.io,thaJeztah/docker.github.io,bdwill/docker.github.io,alexisbellido/docker.github.io,menglingwei/denverdino.github.io,menglingwei/denverdino.github.io,BSWANG/denverdino.github.io,shin-/docker.github.io,denverdino/denverdino.github.io,londoncalling/docker.github.io,JimGalasyn/docker.github.io,docker/docker.github.io,bdwill/docker.github.io,johnstep/docker.github.io,thaJeztah/docker.github.io,JimGalasyn/docker.github.io,thaJeztah/docker.github.io,joaofnfernandes/docker.github.io,johnstep/docker.github.io,sanscontext/docker.github.io,phiroict/docker,aduermael/docker.github.io,aduermael/docker.github.io,docker/docker.github.io,shubheksha/docker.github.io,shin-/docker.github.io,sanscontext/docker.github.io,shubheksha/docker.github.io,joeuo/docker.github.io,shin-/docker.github.io,BSWANG/denverdino.github.io,docker-zh/docker.github.io,gdevillele/docker.github.io,sanscontext/docker.github.io,joeuo/docker.github.io,joeuo/docker.github.io,denverdino/denverdino.github.io,bdwill/docker.github.io,phiroict/docker,docker-zh/docker.github.io,jzwlqx/denverdino.github.io,anweiss/docker.github.io,londoncalling/docker.github.io,gdevillele/docker.github.io,docker-zh/docker.github.io,jzwlqx/denverdino.github.io,gdevillele/docker.github.io,docker/docker.github.io,joaofnfernandes/docker.github.io,alexisbellido/docker.github.io,londoncalling/docker.github.io,joeuo/docker.github.io,LuisBosquez/docker.github.io,joaofnfernandes/docker.github.io,denverdino/docker.github.io,johnstep/docker.github.io,phiroict/docker,BSWANG/denverdino.github.io,jzwlqx/denverdino.github.io,troy0820/docker.github.io,gdevillele/docker.github.io,shin-/docker.github.io,denverdino/docker.github.io,joeuo/docker.github.io,jzwlqx/denverdino.github.io,troy0820/docker.github.io,docker-zh/docker.github.io