NEPT-1534: Double-check component implementation for inconsistencies:

[ademarco]

In particular:

• Component is using but we currently use instead
• is not mentioned in documentation but we are using it, clarify this
• For contacts, we use type auteur, we don't use 'planningUnit' neither 'translationUnit': check which one to keep
• In EC\Poetry\Messages\Components\ReturnAddress 'WebService' should start with lowercase in (2x) 'expression' => 'this.getType() == "webService"': Check this.
• "ReturnAddress()->setRemark" call: Why is it mandatory to call it when we introduce a blank? the blank value cannot be the default value?
• Add tests for all tasks above

[ademarco]

We are removing this temporarily, we will need to better check it:

class Identifier extends AbstractComponent
...
        $metadata->addConstraint(new Assert\Expression([
            'expression' => 'this.getSequence() || this.getNumber() ',
            'message' => 'An identifier must have a number or a sequence.',
        ]));
        $metadata->addConstraint(new Assert\Expression([
            'expression' => '(this.getSequence() && this.getNumber()) == false ',
            'message' => 'An identifier can\'t have both a number and a sequence.',
        ]));