Feature: Introduce localized pageTitleFormat placeholder (LLL:EXT:) 

Description 

It's a valid use-case to use a pageTitleFormat for the person profile detail page view as HTML page title including localized text as placeholders and could be implemented using the PSR-14 event ModifyProfileTitlePlaceholderReplacementEvent dispatched in the ProfileTitleProvider.

Localization is a generic feature and it's most likely that it's use-full for a broader audience this change adds now support for localization placeholder in the format:

%%LLL:EXT:<extension-key>/Resources/.../locallang.xlf:identifier%%

Note that no context fallback detection is made like within fluid templates or extbase context areas and a valid relative path for the default language file within a extension needs to be provided.

Functional tests are added to cover the new feature basically and provide some examples, using a dedicated test fixture extension.