feat: respect X-Forwarded-Proto (DEV-3499)

[siers]

X-Forwarded-Proto is now being respected in both info.json and knora.json. Repetition slightly reduced. Both are tested in test/e2e.

See also:
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto

[linear]

DEV-3499 HTTPS URL when requesting info.json

[codecov]

Codecov Report

Attention: Patch coverage is 11.11111% with 8 lines in your changes missing coverage. Please review.

Project coverage is 22.5%. Comparing base (9463410) to head (7df3a92).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/SipiHttpServer.cpp	0.0%	2 Missing and 4 partials ⚠️
shttps/Connection.cpp	33.3%	0 Missing and 2 partials ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
shttps/Connection.h	40.0% <ø> (-1.5%)	⬇️
shttps/Connection.cpp	26.4% <33.3%> (+<0.1%)	⬆️
src/SipiHttpServer.cpp	20.9% <0.0%> (+0.1%)	⬆️

... and 2 files with indirect coverage changes

[subotic]

Very good. Thank you!