Also re-order lexicographically.

Note that I did not exhaustively test this... there could be edge cases
depending on the python version. But I think we should be okay because
`tox.ini` is currently testing using with unpinned versions, so I think
we're already running these versions in our test suite.

Fix a deprecation warning in the newest version.

Previously there were two methods:
* `_find_coordinator_id()`
* `_find_many_coordinator_ids()`

But they do basically the same thing internally. And we need the plural
two places, but the singular only one place.

So merge them, and change the function signature to take a list of
`group_ids` and return a dict of `group_id: coordinator_id`s.

As a result of this, the `describe_groups()` command should scale better
because the `_find_coordinator_ids()` command issues all the requests
async, instead of sequentially blocking as the `described_groups()` used
to do.

Small cleanup leftover from https://github.com/dpkp/kafka-python/pull/2035

* Add consumergroup related errors
* Add DeleteGroups to protocol.admin
* Implement delete_groups feature on KafkaAdminClient

Fix initialization order in KafkaClient

Currently there's no way to pass timeout to check_version if called from admin.