Add configuration knob for max queries per connection

[Arkelenia]

1. Why is this pull request needed and what does it do?

Coredns underlying DNS library exposes a MaxTCPQueries parameter that controls how many queries can be sent on a given connection and defaults to 128 if unset. This previous change to coredns changed the default to -1 (unlimited). This PR is an attempt at making this value configurable.

This new parameter is added in the timeouts plugin because it is the closest plugin I could think of but I might be wrong.

2. Which issues (if any) are related?

This is related to the regression mentioned in this issue https://github.com/coredns/coredns/issues/6803

3. Which documentation changes (if any) need to be made?

The documentation of the timeouts plugin needs to be changed to add the new parameter.

4. Does this introduce a backward incompatible change or deprecation?

It doesn't since the new parameter still defaults to "unlimited".