[WIP] Fixes ENV overriding config

[sreichel]

Description (*)

Work in progress ...

• updates tests to test agains DB
• fixes Mage::getStoreConfig()
• fixes override existing DB values

Broken ...

• unittests for non-existing stores/websites (?)

Related Pull Requests

• see New feature: override configurations with env variables #3863

Fixed Issues (if relevant)

• see Issues with ENV-variables override #4257

Manual testing scenarios (*)

Set php ENV variables ... for DDEV (to match tests)

web_environment:
    - OPENMAGE_CONFIG__DEFAULT__GENERAL__STORE_INFORMATION__NAME=ENV default
    - OPENMAGE_CONFIG__DEFAULT__GENERAL__FOO-BAR__NAME=ENV default dashes
    - OPENMAGE_CONFIG__DEFAULT__GENERAL__FOO_BAR__NAME=ENV default underscore
    - OPENMAGE_CONFIG__DEFAULT__GENERAL__ST=ENV default invalid
    - OPENMAGE_CONFIG__WEBSITES__BASE__GENERAL__STORE_INFORMATION__NAME=ENV website
    - OPENMAGE_CONFIG__WEBSITES__BASE-AT__GENERAL__STORE_INFORMATION__NAME=ENV website dashes
    - OPENMAGE_CONFIG__WEBSITES__BASE_CH__GENERAL__STORE_INFORMATION__NAME=ENV website underscore
    - OPENMAGE_CONFIG__WEBSITES__BASE__GENERAL__ST=ENV website invalid
    - OPENMAGE_CONFIG__STORES__GERMAN__GENERAL__STORE_INFORMATION__NAME=ENV store
    - OPENMAGE_CONFIG__STORES__GERMAN-AT__GENERAL__STORE_INFORMATION__NAME=ENV store dashes
    - OPENMAGE_CONFIG__STORES__GERMAN_CH__GENERAL__STORE_INFORMATION__NAME=ENV store underscore
    - OPENMAGE_CONFIG__STORES__GERMAN__GENERAL__ST=ENV store invalid

Comments

This is not nearly perfect, but may help @pquerner and others to debug.

This PR is NOT based on main-branch, but on #4236.

See ec2c8a9 for relevant changes.

@pquerner @boesbo please check.

[sreichel]

Clean PR later ...