Add pipx and virtual env support

[pgrenaud]

Related to #907. This PR:

• Fix pipx package name for Arch (pacman).
• Add install pipx tools logic. Add the base logic to support pipx tools.
  • Remove the changes introduced by 56a4ce7 and 7f8717f.
• Install pipx tools with pipx and update corresponding paths in reconftw.sh. This is the bulk of the work were package paths needed to be updated.
  • Since Interlace and wafw00f are now installed by pipx, the special configurations for them are no longer needed.
• Install python requirements in individual virtual environment. Since some of the python dependent tools don't support pipx, we need to install them by hand. To avoid the Externally Managed Environments issue (as mentioned in Multiple issues when installing on Ubuntu 24.04 #907), we need to install them in individual virtual environment.
  • Restore support for tools with a requirements.txt file. This feature was present in the past but was removed by c46277a.
  • Update corresponding paths in reconftw.sh for tools that uses a virtual environment. This is the bulk of the work were package paths needed to be updated.
• Remove the requirements.txt file as it is no longer required.