cairo-run execution in parallel

[rkdud007]

Context

currently as we finish preprocess for generating input, we run binary in same thread. Ideally should spawn multiple thread so that other request via input file will not get block.

And as spawning multiple run means, we are chunking processing step ( get input.json -> generate output.json & PIE ) to be expose seperate, this should happen after #80 make it stateful to divide the step of preprocess and process.