Tests: Bluetooth: Mesh: Add BLOB Server persistent storage BSim tests

These tests stop BLOB Transfer after BLOB Server reaches every phase
by rebooting devices. After restart, Server recovers transfer and client
continues to the next one. On second pass, Server stops after first
block completes and suspends itself, and after reboot continues to
completion.

Signed-off-by: Krzysztof Kopyściński <krzysztof.kopyscinski@codecoup.pl>