Implement / fixes WEB-306.
We can't rely on default tls backend for reqwest and hope to work with
every target platform we support, due to several constraints. Some
target cannot use -sys (openssl-sys), and some can't build rustls due to
trasnsitive dep support issue.
PR creates explicit opt-in features for those and let upstream
application can specify what they need. `next-dev` currently sets
`native-tls` as default for the general dev workflow conveniences, but
that doesn't mean we promote it as default feature set - next-swc, or
other like standalone turbopack will configure features by themselves
when build binaries for their own.
9e7bf34b21