Clean up code.

[a-t-0]

• Think about the filenaming structure and improve it.
  • Some files are called custom_install.. even though they do not install anything.
• Make code base shellcheck compliant.

[mohitsaxenaknoldus]

I can work on this.

[create-issue-branch]

Branch issue-20-Clean_up_code created!

[mohitsaxenaknoldus]

PR: #38