refactor: project structure

[mabdh]

following project structure standard applied to #entropy

[coveralls]

Pull Request Test Coverage Report for Build 2368610846

• 1483 of 1823 (81.35%) changed or added relevant lines in 30 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.3%) to 81.038%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/metrics/statsd_monitor.go	7	8	87.5%
core/user/context.go	9	11	81.82%
internal/server/v1beta1/type.go	18	20	90.0%
pkg/grpc_interceptor/user.go	18	20	90.0%
internal/server/health/health.go	0	3	0.0%
internal/server/v1beta1/comment.go	83	88	94.32%
internal/server/v1beta1/search.go	13	18	72.22%
internal/server/v1beta1/server.go	30	36	83.33%
core/discussion/comment.go	0	8	0.0%
internal/server/v1beta1/lineage.go	32	42	76.19%

Totals
Change from base Build 2356199783:	-0.3%
Covered Lines:	4530
Relevant Lines:	5590

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💛 - Coveralls

[StewartJingga]

LGTM