experimental.config.utils.schema: JSON schema for schema object.

Dev. issue: https://github.com/tarantool/tarantool/issues/10636

Product: Tarantool
Since: 3.3.0
Root document: https://www.tarantool.io/en/doc/latest/reference/reference_lua/config/utils_schema/
SME: @ mandesero

Details

Connected with #4659, #4660

Brief API description
The schema object has the new method:

• Generate JSON schema as lua table

<schema object>:jsonschema() -> lua table

Detailed API description
Example:
You can obtain the JSON schema representation of a ,
encode it using json.encode(), and integrate it with tools like
VSCode or similar.

local json = require('json')
local schema = require('experimental.config.utils.schema')

local my_schema = schema.new('my_schema', schema.record({
    name = schema.scalar({
        type = 'string'
    }),
    list = schema.array({
        items = schema.scalar({
            type = 'string'
        })
    }),
}))

local json_schema = json.encode(my_schema:jsonschema())
...

Requested by @mandesero in https://github.com/tarantool/tarantool/commit/ea5d3cd8b07efc825b3e162e2acf8e4d97e76407.

Start with the linked root document for experimental.config.utils.schema and use the API description and example in this issue as the requirements. Document the jsonschema() method, its Lua-table return value, and the JSON encoding example; the root document should clearly explain how the result can be used with tools such as VSCode.