Refactor config loading for handling volumes_from in v2.
Refactor config loading for handling volumes_from in v2.

Signed-off-by: Daniel Nephin <6347c07ae509164cffebfb1e2a0d6ed64958db19@docker.com>

LuisBosquez/docker.github.io,denverdino/docker.github.io,phiroict/docker,jzwlqx/denverdino.github.io,johnstep/docker.github.io,danix800/docker.github.io,denverdino/denverdino.github.io,LuisBosquez/docker.github.io,joeuo/docker.github.io,thaJeztah/compose,andrewgee/compose,joeuo/docker.github.io,KalleDK/compose,jrabbit/compose,johnstep/docker.github.io,anweiss/docker.github.io,danix800/docker.github.io,BSWANG/denverdino.github.io,shin-/compose,vdemeester/compose,tiry/compose,aduermael/docker.github.io,michael-k/docker-compose,moxiegirl/compose,BSWANG/denverdino.github.io,mdaue/compose,shin-/docker.github.io,tiry/compose,gdevillele/docker.github.io,phiroict/docker,JimGalasyn/docker.github.io,joaofnfernandes/docker.github.io,schmunk42/compose,phiroict/docker,docker/docker.github.io,menglingwei/denverdino.github.io,sanscontext/docker.github.io,JimGalasyn/docker.github.io,alexisbellido/docker.github.io,shin-/docker.github.io,swoopla/compose,rillig/docker.github.io,danix800/docker.github.io,docker/docker.github.io,thaJeztah/compose,docker-zh/docker.github.io,jzwlqx/denverdino.github.io,sanscontext/docker.github.io,menglingwei/denverdino.github.io,danix800/docker.github.io,swoopla/compose,phiroict/docker,joeuo/docker.github.io,anweiss/docker.github.io,thaJeztah/docker.github.io,alexisbellido/docker.github.io,denverdino/docker.github.io,rillig/docker.github.io,andrewgee/compose,docker-zh/docker.github.io,menglingwei/denverdino.github.io,menglingwei/denverdino.github.io,denverdino/docker.github.io,londoncalling/docker.github.io,docker-zh/docker.github.io,moxiegirl/compose,troy0820/docker.github.io,thaJeztah/docker.github.io,sdurrheimer/compose,JimGalasyn/docker.github.io,JimGalasyn/docker.github.io,troy0820/docker.github.io,dnephin/compose,thaJeztah/docker.github.io,denverdino/denverdino.github.io,twitherspoon/compose,gdevillele/docker.github.io,rillig/docker.github.io,jrabbit/compose,shin-/docker.github.io,bdwill/docker.github.io,joaofnfernandes/docker.github.io,jzwlqx/denverdino.github.io,rillig/docker.github.io,shubheksha/docker.github.io,phiroict/docker,denverdino/docker.github.io,BSWANG/denverdino.github.io,denverdino/denverdino.github.io,docker/docker.github.io,dnephin/compose,joaofnfernandes/docker.github.io,schmunk42/compose,gdevillele/docker.github.io,BSWANG/denverdino.github.io,sanscontext/docker.github.io,thaJeztah/docker.github.io,dbdd4us/compose,gdevillele/docker.github.io,alexisbellido/docker.github.io,menglingwei/denverdino.github.io,LuisBosquez/docker.github.io,funkyfuture/docker-compose,alexisbellido/docker.github.io,bdwill/docker.github.io,shin-/docker.github.io,londoncalling/docker.github.io,KalleDK/compose,docker-zh/docker.github.io,shin-/compose,funkyfuture/docker-compose,thaJeztah/docker.github.io,mdaue/compose,alexisbellido/docker.github.io,aduermael/docker.github.io,denverdino/compose,gdevillele/docker.github.io,shubheksha/docker.github.io,denverdino/denverdino.github.io,BSWANG/denverdino.github.io,michael-k/docker-compose,LuisBosquez/docker.github.io,shubheksha/docker.github.io,bdwill/docker.github.io,anweiss/docker.github.io,bdwill/docker.github.io,GM-Alex/compose,twitherspoon/compose,johnstep/docker.github.io,jzwlqx/denverdino.github.io,aduermael/docker.github.io,denverdino/denverdino.github.io,jzwlqx/denverdino.github.io,docker/docker.github.io,LuisBosquez/docker.github.io,anweiss/docker.github.io,shin-/docker.github.io,denverdino/docker.github.io,docker-zh/docker.github.io,aduermael/docker.github.io,hoogenm/compose,dbdd4us/compose,sanscontext/docker.github.io,vdemeester/compose,hoogenm/compose,londoncalling/docker.github.io,docker/docker.github.io,johnstep/docker.github.io,shubheksha/docker.github.io,johnstep/docker.github.io,troy0820/docker.github.io,sanscontext/docker.github.io,sdurrheimer/compose,troy0820/docker.github.io,denverdino/compose,joeuo/docker.github.io,joaofnfernandes/docker.github.io,GM-Alex/compose,anweiss/docker.github.io,shubheksha/docker.github.io,bdwill/docker.github.io,JimGalasyn/docker.github.io,joeuo/docker.github.io,londoncalling/docker.github.io,londoncalling/docker.github.io,joaofnfernandes/docker.github.io