Refactor file store constructor #605

Job	Run time
fmt	19s
build	2m 47s
clippy	2m 14s
tests (coverage-map)	1m 30s
tests (coverage-point-calculator)	1m 14s
tests (ingest)	1m 52s
tests (reward-scheduler)	47s
tests-postgres (boost-manager)	2m 26s
tests (task-manager)	48s
tests-postgres (iot-config)	2m 38s
tests-postgres (file-store)	2m 1s
tests-postgres (iot-packet-verifier)	3m 57s
tests-postgres (iot-verifier)	2m 38s
tests-postgres (mobile-config)	2m 30s
tests-postgres (mobile-packet-verifier)	2m 16s
tests-postgres (mobile-verifier)	2m 45s
build-release	0s
	32m 42s

Provide feedback