ptrecrypt / ptreencrypt - (batch) encrypt existing encrypted files

[clach04]

Split from #1

ptrecrypt / ptreencrypt - (batch) encrypt existing encrypted files with new encryption key/container(cipher), rather than calling ptcipher and then deleting files

Would be useful for #169 to compare performance impact, perhaps using #146

Ideas

• Use input parameter of output file extension to determine new encryption
• By default stop if destination derived file name already exists, with flag to allow continue
  • Options would be skip (carry on) and overwrite
• Have option to delete sources files after successful conversion
• Initial version use same password
• Later support different password, can then retain format and simply bulk/batch/mass password change/update. See existing tools https://hg.sr.ht/~clach04/pytombo/browse/src/find_enc_notes.py?rev=tip, see if can be used as initial basis for new tool

[clach04]

In progress https://github.com/clach04/puren_tonbo/tree/issues_170_ptrecrypt