Make payjoin-cli msrv 1.63.0

[DanGould]

• Swap blocking rouille for async hyper, since rouille depends on hyper anyhow.
• Lower clap version to support msrv
• Use ureq insetad of reqwest to support msrv (and reduce binary size as a side effect)
• Combine now shared msrv build between tests
• Share a workspace, allowing better editor & build support now that we're on the same msrv

[DanGould]

msrv +1.63 requires at a minnimum

cargo +1.63.0 update -p time --precise 0.3.20
cargo update -p regex --precise 1.9.6

And reqwest will have to be swapped out