Deprecate `NullTrustManager`

[acogoluegnes]

Just a matter of name, create a AlwaysTrustTrustManager clone, and remove NullTrustManager in 5.0.

See #230.

[michaelklishin]

How about TrustEverythingTrustManager or MostNaiveTrustManager?

[acogoluegnes]

I prefer my AlwaysTrustTrustManager over TrustEverythingTrustManager, but I admit the 2 Trusts in a row don't make it very readable.
I like MostNaiveTrustManager (it's so naive, it lets everyone pass), but it's not immediately obvious that it trusts everyone.
Let's go with TrustEverythingTrustManager.

[michaelklishin]

OK, I'm fine with that.

[mhewedy]

My comment has nothing to do with RabbitMQ...

I wanted to have a proper name for my "trust all TM", and I come up with NullTrustManager (in the same way as /dev/null)

But I find you changed the name, and then I liked TrustEverythingTrustManager except that it is a very long name.