qt: Overhaul ReceiveRequestDialog

Summary:

If master is compiled without QR support, the "Request payment to..." dialog looks ugly

Other minor changes:

• "URI" abbreviation is not translated now
• wallet name is shown if available

This is a backport of core#17597 [1/2]
https://github.com/bitcoin/bitcoin/pull/17597/commits/68288ef0c15522799d4bf6239d2ae1e8086b5abf

Test Plan:
ninja && ninja check

Build without QR code support and inspect the result.

cmake .. -GNinja -DENABLE_QRCODE=OFF
ninja && src/qt/bitcoin-qt

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D9922