[!!!][TASK] Adjust to search API changes in TYPO3CR

* wire signals from Node instead of NodeDataRepository
* no longer index __persistenceObjectIdentifier
* change slots to accept Node instead of NodeData
* adjust NodeIndexer to work with Node instead of NodeData
* build Node instances for indexing in NodeIndexCommandController

With this change the id of all documents indexed in ES changes, so a
reindexing is needed.
Merge pull request #16 from Flowpack/search-api-adjustments

[!!!][TASK] Adjust to search API changes in TYPO3CR