Merge #14494: Error if # is used in rpcpassword in conf

Summary:
0385109444646561a718f34ae437b7e0e4d4d5bc Add test for rpcpassword hash error (MeshCollider)
13fe258e91e7a92326aedf151c571994166a06d4 Error if rpcpassword in conf contains a hash character (MeshCollider)

Pull request description:

Fixes #13143 now #13482 was merged

Tree-SHA512: e7d00c8df1657f6b8d0eee1e06b9ce2b1b0a2de487377699382c1b057836e1571dac313ca878b5877c862f0461ba789a50b239d2a9f34accd8a6321f126e3d2a

Backport of Core PR14494
https://github.com/bitcoin/bitcoin/pull/14494/files

Depends on D5009 and D5011

Test Plan:

ninja check
test_runner.py feature_config_args

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D5012