dnsdist: Add DoH3 headers, query string, path and scheme bindings

[rgacogne]

Short description

The DoH ones have been there for a long time, but the DoH3 ones were missing. Note that we still don't have the ability to set a HTTP response for DoH3 queries (including response maps) and SNI is still missing (Quiche does not make that last one easy).

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)

[coveralls]

Pull Request Test Coverage Report for Build 12549052014

Details

• 128 of 139 (92.09%) changed or added relevant lines in 5 files are covered.
• 7617 unchanged lines in 147 files lost coverage.
• Overall coverage increased (+2.2%) to 64.851%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pdns/dnsdistdist/test-dnsdisttcp_cc.cc	0	2	0.0%
pdns/dnsdistdist/dnsdist-lua-ffi.cc	44	48	91.67%
pdns/dnsdistdist/doh3.cc	33	38	86.84%

Files with Coverage Reduction	New Missed Lines	%
pdns/dnsdistdist/dnsdist-session-cache.cc	1	62.86%
pdns/auth-catalogzone.hh	1	66.67%
pdns/dnsdistdist/test-dnsdistrules_cc.cc	1	95.15%
pdns/recursordist/nod.hh	1	92.59%
pdns/dnsdistdist/dnsdist-crypto.cc	1	76.01%
pdns/test-dnsrecords_cc.cc	2	95.97%
pdns/dnsdistdist/test-dnsdist-lua-ffi.cc	2	99.59%
pdns/epollmplexer.cc	2	85.0%
pdns/json.cc	2	83.33%
pdns/recursordist/rec-tcpout.cc	2	63.49%

Totals
Change from base Build 12508806594:	2.2%
Covered Lines:	126213
Relevant Lines:	163857

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💛 - Coveralls

[miodvallat]

LGTM