Add functions for validation and comparison keys to key_def module #9863
Description
There are no functions to validate a key and compare two keys in the key_def module:
tarantool> key_def
---
- merge: 'function: 0x40e6e2d8'
extract_key: 'function: 0x40e6e1a8'
new: 'function: 0x40e6e148'
totable: 'function: 0x40e6e240'
compare: 'function: 0x40e6e1f8'
compare_with_key: 'function: 0x40e6e170'
...We need them for https://github.com/tarantool/aeon/issues/20 and https://github.com/tarantool/aeon/issues/25. It should be fairly easy to add them because they're already available in C so we just need to export them to Lua.