fix(http-host-matching): make http host matching case insensitive

[anthoturc]

this will ensure that the host name matching is RFC compliant w.r.t DNS names (i.e. case-insensitive)

[adleong]

I notice that in some places we're normalizing to lowercase and in other places we're doing a case insensitive compare. Do we need both?

[anthoturc]

I think we need both.

I had added the normalization for the case where the HTTPRoute had a host defined in an unexpected way "Example.Com" vs "example.com" (which are the same).

The case-insensitive check is there for the runtime Host header/authority value (which can be anything). During my testing, I saw that the http crate's host() function (on the authority) would return the original Host header without normalizing it.

[anthoturc]

after some offline discussion, Alex and I agreed that we don't strictly need the normalization logic since the case-insensitive match check covers us even when the control plane sends "weird" looking host names.