api: metrics configuration

[DifferentialOrange]

This PR introduces metrics.cfg{} -- a single entrypoint to setup the module:

• include and exclude options with the same effect as in enable_default_metrics(include, exclude);
• labels options with the same effect as set_global_labels(labels);
• values and effect (like default metrics callbacks) are preserved between reloads;
• does not deal with external features like cartridge HTTP setup.

It is a prerequirement to box.cfg{} metrics configuration after embedding.

Some features were deprecated to make API more consistent and stable:

• explicit {} include with the default meaning ("include all"),
• invalid metric names.

Using the deprecated features logs warning for existing handles and throw errors for new API like metrics.cfg{}.

See comments for more info.

I didn't forget about

• [x] Tests
• [x] Changelog
• [x] Documentation (README and rst)
• [x] Rockspec and rpm spec

Part of tarantool/tarantool#7725