Support passing binary HTTP query keys and values

https://www.rfc-editor.org/rfc/rfc3986#section-3.4:

query         = *( pchar / "/" / "?" )
pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"
unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
pct-encoded   = "%" HEXDIG HEXDIG
sub-delims    = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="
ALPHA         =  %x41-5A / %x61-7A   ; A-Z / a-z
DIGIT         =  %x30-39             ; 0-9
HEXDIG        =  DIGIT / "A" / "B" / "C" / "D" / "E" / "F"

Relates to https://gitlab.com/gitlab-com/ops-sub-department/section-ops-request-for-help/-/issues/451+.

I've tested this with GDK (kas + agentk) and against staging. All works fine.