Improvements for the UI

[Senyoret1]

Did you run make format && make check?
The go code was not changed. npm run lint and npm run build were used.

Changes:

• The pagination control is now in the correct position in mobile devices.
• Now a small alert is shown at the botom-right corner of the screen when there is a comunication problem with the back-end, to make it more notorious that the info may not be updated.

How to test this PR:
Close the visor back-end while the ui is open, after the following failed connection you should see the small red alert at the bottom-right corner indicating thing problem.