Support for vanitygen Protkey

[The-Bootloader]

Is your feature request related to a problem? Please describe.
The legacy vanitygen software can generate encrypted keys called Protkey and starting with Ps.
https://github.com/samr7/vanitygen

Describe the solution you'd like
Ability to put the corresponding Address and Protkey into a file, and let btcrecover.py decrypt it

Describe alternatives you've considered
There is no other option. vanitygen no longer compiles on modern OpenSSL versions.

Additional context
Example keys from https://bitcointalk.org/index.php?topic=2234266.0:

Address: 1AStRLSHpGRbYFKxv2TJJmkZkUDmqurWwq
Protkey: PsTNSPvWJF8mNm2JVSnwsX9fSFymdvvXZxecSABwpXrnkHVfUQi4qt8ekDTcgCm7qBAf

[3rdIteration]

I haven't had any trusted recovery requests for this issue nor requests for it to be directly sponsored, so it probably won't get implemented until one of those two things happen. (Unless you want to do it and bring a PR)