Adding Theme support

[gtref]

Description

Implament a simple ui theme setting in either the top bar or bottom bar that allows users to select between a dark theme or a light theme. Also adding a folder themes that should contain all themes created for this.

tasks

• Create a themes/ directory to store all theme metadata.
• Add a ui element to select the theme.
• Add the selector in the javascript so that it actually changes the editor theme.
• Ensure that the themes either persist (Optional) on each use or offer clean application.

Build steps

Once your changes are complete, Please make sure you have node js installed. If so please run

npm install

This will install all needed npm packages. Then run

npm run dist:win

This command packs the installer. Though this step is optional because for quick testing you will want to run

npm start

After you complete this please in the same PR update the file CONTRIBUTORS.md with your details if you would like to be acknowledged

[NCS22]

I will start this issue today, I hope I can finish it by the end of the day

[NCS22]

I have a question, do you want the Themes to be 100% personalized or do I have to create 3 to 5 themes and apply them into the application. I recommend the latest option but I will do the one you are more comfortable with.

[gtref]

Can you do the last option? Creating the like 2 or 3 to 5 themes?

[gtref]

I have Merged your pull request. Thank you for doing this.