Remove another few lines of unused code.

Remove .drop, .getobject, .setobject, .cursor from soif

Conflicts:
	src/ffisyms.cc

Remove an unused global view at the database.

Set a memory limit in Phia. Fix the quota accounting.

* remove document expire
* remove snapshotting, anticache, memory-only modes
* remove unused box.cfg.phia settings

Remove "optimized" autocommit code when working with a single index,
tarantool always creates a transaction in engine even for
autocommit mode. This optimization, in other words, could
(potentially) save only a little bit of CPU in case of
autocommit and only-primary-key space.