Commit Message: local rate limit: add new rate_limits api to the filter's api
Additional Description:

In the previous local rate limit, the rate_limits field of route is used to generate the descriptor entries. Then the generated entries will be used to match a token bucket which is configured in the filter configs (route level, vhost level, etc).

However, it make the configuration very complex, and cannot cover some common scenarios easily. For example, give a specific virtual host X and a special route Y that under this virtual host X.

We want to provides a virtual host level rate limit for the specific virtual host X, and a route level rate limit for the specific route Y. We hope the configuration of virtual host could works for all routes except the Y.

For most filters, this requirement could be achieved by getting the most specific filter config and applying it. But for the local rate limit, thing become very complex. Because the rate limit configuration is split into rate_limits field of route and the filter config. The local rate limit need to handle these relationship carefully.

This PR try to simplify it.

Risk Level: low.
Testing: n/a.
Docs Changes: n/a.
Release Notes: n/a.
Platform Specific Features: n/a.

Request variables

Key	Value
ref	109949c
sha	e9893ed
pr	36099
base-sha	9244dc9
actor	@wbpcode
message	local rate limit: add new rate_limits support to the filter...
started	1728105482.200271
target-branch	main
trusted	false

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