Decrypt keepass database v3-0x67 ONLY

Features:
  - Optional secret keyfile supported
  - URL quick open in browser
  - Username/password copy and clear
  - Pure CLI, colorful output

Requirements:
  - Python >= 3.6
  - PyCryptodomex >= 3.8 (https://pypi.org/project/pycryptodomex)
  - `firefox` as default browser (or manully specify another one)
  - `xclip -sel c` as clipboard (or manully specify another cmd)

Credits:
  - https://gist.github.com/msmuenchen/9318327
  - https://github.com/libkeepass/libkeepass/tree/master/libkeepass
  - https://github.com/lgg/awesome-keepass#docs-and-articles
  - https://github.com/Evidlo/examples/blob/master/python/kdbx3_decrypt.py