improve dal:validate to reach green status !

[raphael-homann]

to dal:validate command

• add DefinitionValidatorFilterEvent

1. Why is this change necessary?

• dal:validate has many errors, not my fault (Shopware\Core and other)
• I would like to have a full green dal:validate on my own code (so I can use it in my precommit hook)
• I have tables on my database I want to keep, but I don't want to have errors on these tables

2. What does this change do, exactly?

• The entityDefinitions filter is not only hardcoded anymore. I added an event, so every plugin can filter definitions to check
• I added an option --check-unregistered-tables / --no-check-unregistered-tables on dal:validate command.
  by default, nothing changes

3. Describe each step to reproduce the issue or behaviour.

• execute dal:validate, and you will have many errors
• execute dal:validate --no-check-unregistered-tables command, you won't see "Table ... has no configured definition"

4. Please link to the relevant issues (if any).

5. Checklist

• I have rebased my changes to remove merge conflicts
• I have written tests and verified that they fail without my change
• I have created a changelog file with all necessary information about my changes
• I have written or adjusted the documentation according to my changes
• This change has comments for package types, values, functions, and non-obvious lines of code
• I have read the contribution requirements and fulfil them.

[raphael-homann]

hard to check PHP lint and BC check 😅
One wants to add : void to configure method, while the other one does not want