feat: add index for guestOrder field in database.xml

See merge request !37

This commit addresses the event handling within the QUI ERP order process. Instead of returning the
order directly, the changes allow update of the 'c_user' field in the database by using the
customer UUID from the session. Additionally, it now returns the order fetched by hash instead of
the direct order object. This approach is more fail-safe and consistent.

Related: #11

The commit introduces a new index for the `guestOrder` field in the `orders_process` table of
`database.xml`. This will help to optimize database operations related to the `guestOrder` field.

fix: ensure email retrieval and order processing in EventHandler

See merge request !35

This commit addresses two main issues in `EventHandler.php`.
Firstly, the fetching of the email from the `GuestOrder` session is moved at a different location
in the flow where it makes more sense and doesn't get overridden prematurely.

Secondly, an exhaustive condition handling has been added to address cases where there might be a
payment error or async payment error. The method fetches the current order via the URL hash which
could be an `OrderInProcess` or an already existing `Order`.

The commit also ensures that the customer UUID is set correctly if the session exists. An update is
made to the database to accommodate this change.

Minor changes have also been made to spacing and data-type declaration in `GuestOrderUser.php` to
help with readability and consistency.

Related: #11

fix: consider logout for GuestOrderUser -> destroys session

See merge request !32

Multiple updates have been made updating specific software versions and modifying code for email
verification. We updated the phpstan version in phars.xml as well as added a new dependency in
composer.json. We also refactored the EmailVerification class and the associated
sendEmailVerification function. Changes include:

1. Modification of the phars.xml file to use a more recent version of phpstan.
2. Addition of a new software dependency to composer.json.
3. Switching from using the deprecated AbstractVerification class to the LinkVerification class.
4. Adjustments to method signatures and error messaging in EmailVerification class.
5. Changes to the sendEmailVerification function in the GuestOrder class to accommodate the updated
LinkVerification class.

This commit introduces a new feature to the GuestOrderUser class under `src/QUI/ERP/Order/Guest/`.
A logout method is added, which calls the `destroy` function from the `QUI` session, allowing a
guest user to log out.

Related: #10

Next 2.x

See merge request !30

fix: argument #3 must be of type array, ArticleListUnique given

See merge request !29

fix: missing isCompany implementation for guest order

See merge request !28

fix: guest user, uses uuid as user id + price factors were lost

See merge request !24

Related: brassberg/tickets#242

fix: phpstan level 5

See merge request !23

Related: #9

feat: guest login use no longer an event to display guest button in order process

See merge request !22

Related: template-cologne#111

Add QUIQQER Tooling

See merge request !13

fix: guest user must be compatible with nobody user

See merge request !20