To work with Calcite and Tarantool the planner needs to store values
in the plan leaf nodes. These values should be defined with exact types.
At the moment we need only several primitive types:
- boolean
- null
- number (decimal from decnumber library)
- string

As the planner analyzes SQL, it has to work with tree-valued logic
(3VL). At the moment we'll need only equivalence operation, so it
was implemented for the values in a 3VL manner.

Change algorithm for working with cluster schema (#18). Before change schema
was parsed from string on every query.Now schema store in global state
and update at first query after new cartridge schema applying.

Also rust-fmt was applied.

Lua functions call was added. It needs because now impossible get this information from tarantool-rust module.

Our CI linter uses 'cargo clippy -- -Dclippy::all -Wclippy::pedantic'
command that previously failed due to multiple errors and warnings.
Current commit fixes all of them and make linter pass. The price
was high - some functions changed their API, some structures were
renamed. But all the warnings and errors seemed reasonable, so I
believe it is not a big deal now.