fix nighlty build

[aliemjay]

for -http: the latest nightly catched a soundness bug in Handler, FromRequest and Responder. Fix it by forcing the bound where Req: 'a on the associated types.

for -web: the same nightly version introduced regression in TAIT that specifically affects impls with borrowed request types. Most of the diff in -web is to workaround this regression:

1. add the bound 'S: 's' on FromRequest impls.
2. async block not captures req in Responder impls.
3. middleware impl are impossible to be general enough (unless we abandon TAIT from the impl)

This regression should hopefully be fixed soon and we can then revert these workarounds.

upstream tracking issue: rust-lang/rust#95922

[fakeshadow]

Do you mind if we keep this PR open for a bit until the regression is fixed? Master branch is guaranteed only to build on 1.61.0-nightly (1bfe40d11 2022-03-18) therefore we can keep the code as is for now.(with middleware works)