rec: add feature to read TLS key info from an encrypted PKCS12 (pfx) file for the embedded web server

[omoerbeek]

Short description

This feature depends on the time crate, which in itself depends on modern (>= 1.88) rust build environment.
Rather than pinning the time crate to an old version, add the infra to check the cargo/rustc version used, so we can enable the feature if it is OK. Use a feature check in the tests to see if we must skip the test or not.

You'll note that with our current CI build, the test is skipped as the feature is not enabled. I have a PR brewing to update the cargeo/rustc version used in CI. After that the feature and test wil be enabled.

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document, including the AI Policy, and added a "Signed-off-by" to my commits
• 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 21941309983

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• 6877 unchanged lines in 80 files lost coverage.
• Overall coverage increased (+0.01%) to 71.591%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pdns/recursordist/ws-recursor.cc	0	1	0.0%

Files with Coverage Reduction	New Missed Lines	%
pdns/iputils.hh	1	75.62%
pdns/recursordist/sortlist.hh	1	75.0%
pdns/dnsname.hh	2	91.64%
pdns/dnstap.cc	2	72.73%
pdns/recursordist/secpoll-recursor.cc	2	52.81%
pdns/ednscookies.hh	3	72.73%
pdns/packethandler.cc	3	72.25%
pdns/rcpgenerator.cc	3	89.97%
pdns/recursordist/rec-nsspeeds.hh	3	90.7%
pdns/recursordist/test-syncres_cc2.cc	3	79.32%

Totals
Change from base Build 21940932318:	0.01%
Covered Lines:	129572
Relevant Lines:	165967

---

💛 - Coveralls

[miodvallat]

Looking good but I am too rustic to know about rust.

[rgacogne]

Looks good to me!

[omoerbeek]

Var renamed and rebased to pick up the new Rust compiler