matrix: add docker env boilerplate

[l5yth]

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[codecov]

Codecov Report

❌ Patch coverage is 96.81275% with 16 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
matrix/src/config.rs	97.57%	10 Missing ⚠️
matrix/src/main.rs	77.27%	5 Missing ⚠️
matrix/src/cli.rs	98.52%	1 Missing ⚠️

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