[Software] Add a theme toggle button to the software

[multiverseweb]

• A theme toggle button should be added on the top-right side of the software.
• It should be visible on every tab.
• The design should match with the aesthetic of existing software.
• The color change should be changed across all tabs and graphs in the software upon theme toggle.

[Rohan20-10]

@multiverseweb Please assign this issue to me. I will work on it.

[multiverseweb]

Sure @Rohan20-10, good luck!

[multiverseweb]

@Rohan20-10 as the project has been selected for SWOC, I believe these issues should be resolved asap so that we can introduce better features like extrapolation and integration with Excel, etc. So I'm unassigning you but you can ask for assignment on any issue whenever you are free again! Thanks. 😄

[p0tat0chip]

i would like to work on this issue

[multiverseweb]

Sure @p0tat0chip, assigned. Feel free to reach out if you encounter any doubts.