Mode 1785 - Implemented the "rebuild indexes at startup" feature

Beside implementing the actual feature both the structure of the JSON schema and the AS7 schema have been updated (the old versions were confusing and didn't support all the attributes). Clients can still use the old attributes, which will be used as fall-backs in case the newer version of the schema isn't used.

In addition to the index rebuilding work, this pull request contains a couple of other commits:
- one around the FileSystemConnector the way it handled projections under the root node
- the other one around the test values used by the BinaryStoreTests

This should be merged into 3.1.x and cherry picked into master.