Migrate to bootstrap v5

Migrate to bootstrap v4

Closes #10 (closed)

Overview of what's done:

• migrated deprecated classes to new ones, eg pane -> card, collapse->in to collapse->show and so on
• added new required classes, eg nav-item, to navigation
• changed styles a little bit so it look ok in new version (colors are more vibrant in bootstrap v4, styles of buttons has changed)
• some little changes like added margins
• new icons (bootstrap icons) as glyphicons are not supported in version 4
• increased size of modals so data is more readable as bootstrap version 4 increase size of font

Anyway I have not focus much on look as I plan to migrate to bootstrap v5 soon.

Here some pics