Clean directory structure

[LalitNM]

Is your feature request related to a problem? Please describe.
It is quite difficult to add features like favicon in the present directory structure.

Describe the solution you'd like
Remove all stac_iitmandi (src/stac_iitmandi, static/stac_iitmandi and templates/stac_iitmandi, not sure if listed all ) directories and add their contents in their parent directory

Additional context
This is related to #148. Also see #158 and #160.

[LalitNM]

As suggested by @tusharrao198, it is possible that in future we might need to add some other app in this repository. Then this will be helpful to have separate directories.