Command to upgrade the DXP flavor

[adriendupuis]

Question	Answer
JIRA issue	IBX-3723
Type	feature
Target Ibexa version	v4.5, v4.6 or latter
BC breaks	no

While trying to write a documentation about DXP edition/flavour upgrade (ibexa/documentation-developer#1978), I had to admin that there is too much hacks&tricks. This documentation won't be easy to follow by the reader, and a nightmare to keep up-to-date.

Instead of hacking from outside using shell scripts, I add to test from inside.

Associated services in https://github.com/ibexa/installer/pull/106

Checklist:

• Provided PR description.
• Tested the solution manually.
• Provided automated test coverage.
• Checked that target branch is set correctly (main for features, the oldest supported for bugs).
• Ran PHP CS Fixer for new PHP code (use $ composer fix-cs).
• Asked for a review (ping @ibexa/engineering).

[sonarcloud]

SonarCloud Quality Gate failed.   

1 Bug
0 Vulnerabilities
0 Security Hotspots
21 Code Smells

No Coverage information
46.8% Duplication