Split up controller_spec to match individual controllers

Signed-off-by: Jesse Zhang <jz@pivotallabs.com>
Introduce CompiledPackagesController

[#55022292]

Signed-off-by: Jesse Zhang <jz@pivotallabs.com>
Extract object to actually do export

[#55022292]

Signed-off-by: Jesse Zhang <jz@pivotallabs.com>
404 if release or stemcell not found

[#55022292]

Signed-off-by: Jesse Zhang <jz@pivotallabs.com>