Feature suggestion: Add custom language selection for Share Basic and HowToVerify.txt

[o-techie]

For now, ProofMode use system language to generate Share Basic text. It may be interesting to implement a config option to select other language than the system default.

Also, please, implement a way for the community to add translations for HowToVerify.txt

[n8fr8]

We can definitely get the HowToVerify.txt into our localization system