Migrate CLI codebase into package 'cmd'

[bobheadxi]

🎟️ Ticket(s): Closes #287

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👷 Changes

Mostly just to clean up our root directory.

🔦 Testing Instructions

go build
./inertia

[coveralls]

Pull Request Test Coverage Report for Build 1002

• 19 of 52 (36.54%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 40.966%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cmd/provision.go	1	2	50.0%
cmd/config.go	5	8	62.5%
cmd/env.go	0	3	0.0%
inertia.go	10	13	76.92%
cmd/users.go	0	4	0.0%
cmd/remote.go	1	6	16.67%
cmd/deploy.go	2	16	12.5%

Totals
Change from base Build 992:	0.1%
Covered Lines:	1399
Relevant Lines:	3415

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💛 - Coveralls