EZP-32214: Made purge type configuration using env vars resolvable at compile time

[webhdx]

Question	Answer
JIRA issue	EZP-32214
Type	improvement
Target eZ Platform version	v3.3 - please update x accordingly
BC breaks	no
Doc needed	no

Since we are using ENV variables to setup HTTP Cache purge driver, it's needed to resolve all envs at compile time. This is rather bad solution because ENVs are not designed to be used this way. In order to make it work we need to call Container::resolveEnvPlaceholders to get real values. Previously it was working because config/packages/overrides/*.php files were used and they resolved values themselves.

Checklist:

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

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[alongosz]

#goodChange

[mnocon]

QA approved.

Please remember to remove TMP changes in ezsystems/ezplatform#632 before merging.