added shellcheck in workflow and updated all sh files

[mfgbhatti]

Hi, I have added shellcheck config and updated all sh files with respect to shellcheck. Please note that this is not any update on functionality of alis script but just recommended change by shellcheck in script. I tried to add much information about it in the file.

[picodotdev]

Hello @mfgbhatti, thanks for the PR, this is a nice feature to have for development and script quality.

I must review all changes and the conventions proposed by shellcheck, will take take me some time to review and give a try that all important things keep working.

[mfgbhatti]

No worries.

[picodotdev]

Merged in #220. Thanks for the PR!.