CORE-2073 quotas: implement alter/describe quotas

[pgellert]

This implements the AlterClientQuotas and DescribeClientQuotas Kafka endpoints. These endpoints can be used to configure client quotas stored in the quota store state. Customers will be able to use the rpk cluster quotas alter/describe cli tool to access these endpoints.

Fixes https://redpandadata.atlassian.net/browse/CORE-2073 Fixes https://redpandadata.atlassian.net/browse/CORE-2074

Backports Required

• [x] none - not a bug fix
• [ ] none - this is a backport
• [ ] none - issue does not exist in previous branches
• [ ] none - papercut/not impactful enough to backport
• [ ] v24.1.x
• [ ] v23.3.x
• [ ] v23.2.x

Release Notes

Features

• Implements the Kafka client quota management APIs of KIP 546: AlterClientQuotas and DescribeClientQuotas.

[vbotbuildovich]

new failures in https://buildkite.com/redpanda/redpanda/builds/50197#01900dd0-d6f7-4aa3-9533-422226347f1f:

"rptest.tests.test_si_cache_space_leak.ShadowIndexingCacheSpaceLeakTest.test_si_cache.message_size=10000.num_messages=100000.concurrency=2"

[pgellert]

Force-pushed twice:

• First: to address the code review suggestions above.
• Second: noop, to reorder the functions in client_quotas.cc and move two functions only used by alter into the commit for alter.