Strip input file whitespaces and newlines

[pshenmic]

Issue

Application takes file path of your private key as a command flag, but it does not sanitize whitespaces and newlines, leading to error if your file contains special characters:

thread 'main' panicked at src/commands/register_dpns_name.rs:82:67:
Could not load private key from WIF: Base58(BadByte(10))
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Input data should be sanitized before passing down

Things done

• Added stripping everything over 52 characters for input key data file (wif is 52 chars length) as a temporary solution