Add TestContainer and start using it to reduce overhead #1293

Job	Run time
Linter / yaml-linter	5s
Linter / json-linter	23s
PHP-Linter (8.3) / linter	15s
PHP-Linter (8.5) / linter	14s
PHP-Linter (8.4) / linter	11s
Linter / style-linter	0s
Linter / ecmascript-linter	0s
Unit tests, PHP 8.5, windows-latest	1m 15s
Unit tests, PHP 8.5, ubuntu-latest	24s
Unit tests, PHP 8.4, ubuntu-latest	20s
Unit tests, PHP 8.3, windows-latest	1m 1s
Unit tests, PHP 8.3, ubuntu-latest	21s
Unit tests, PHP 8.4, windows-latest	58s
Security checks	20s
Code coverage	8s
Quality control	31s
Cleanup artifacts	6s
	6m 32s

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