Move styling from front_ui to stylesheets

[cesswairimu]

In the spirit of following rails way lets move the styling on the front_ui/index to stylesheets

To do

Create a file named front_ui.scss under app/assets/stylesheets
Move this block of code to the file
https://github.com/publiclab/mapknitter/blob/main/app/views/front_ui/index.html.erb#L7-L48

Make sure you send a screenshot to make sure we did not break anything

[cesswairimu]

@katungi here you go

[katungi]

@cesswairimu i will work on it asap.