[FEATURE] Provide PHAR file

[eliashaeussler]

Is your feature request related to a problem?

Nowadays, it's pretty common to use tools like PHIVE to execute PHP libraries. We currently offer the installation methods Composer and Docker, but lack support for PHIVE via PHAR archives.

Describe the solution you'd like

On each release, a PHAR file should be generated. The following acceptance criteria must be met:

• Provide locked PB version in PHAR archive
• Allow to execute all commands provided by PB in PHAR archive
• Add E2E test for PHAR file, see https://github.com/CPS-IT/frontend-asset-handler/blob/3.0.0/.github/workflows/tests.yaml#L89-L122
• Include PHAR files in releases, see https://github.com/CPS-IT/frontend-asset-handler/blob/3.0.0/.github/workflows/release.yaml#L9-L48
• Document usage at https://project-builder.cps-it.de/getting-started.html
• (Optionally) register PHAR file at PHIVE, see https://phar.io/distribute-your-own.html

Describe alternatives you've considered

No response

Additional context

No response