Add error field 'name'

[TarantoolBot]

Related dev. issue(s): tarantool/tarantool#9875

Product: Tarantool
Since: 3.1
Root document: https://www.tarantool.io/en/doc/latest/reference/reference_lua/box_error/error_object/
SME: @ nshy

Details

The value is equal to name used on creation.

 tarantool> box.error.new(box.error.ILLEGAL_PARAMS, 'foo').name
---
- ILLEGAL_PARAMS
...

Requested by @ nshy in tarantool/tarantool@2bf9579.