Fix icons not showing on WSL Ubuntu

[vishwamartur]

Related to #345

Add instructions for installing and configuring fonts on WSL Ubuntu.

• README.rst

  • Add a section for installing and configuring fonts on WSL Ubuntu.
  • Provide steps to install necessary packages and configure font settings.
  • Mention DejaVu and Sarasa Term SC fonts as potential solutions.

• samples/DejaVuSansMono.md

  • Add a note about the issue with icons on WSL Ubuntu.
  • Provide steps to install necessary packages and configure font settings.
  • Mention DejaVu and Sarasa Term SC fonts as potential solutions.

• install.sh

  • Add support for WSL Ubuntu.
  • Install fonts-powerline package on WSL Ubuntu.
  • Set font directory to $HOME/.local/share/fonts for WSL Ubuntu.