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:

• Now the app logs modal window has a limit of 5000 entries, to avoid performance issues making the app unresponsive. If there are more entries, there is a button for showing all the entries.
• A problem that did not let to click on the labeled value components on the DMSG tab of the main page was fixed.
• Now the modal window with the options for labeled elements has a link to the settings page.
• Validation error msgs were added to the modal windows used for configuring the reward address.
• A problem that did not allow to press the language button on small screens on the login page was fixed.
• The deprecated flatMap function was replaced with mergeMap.

How to test this PR:
1 - If you have a lot of logs, after pressing the logs button on the app list, the modal window should show on 5000 entries and a button for opening all the logs if you scroll to the top.
2 and 3 - On the main page, select the DMGS tab and click on the PK of the DMSG server of a visor. The options for changing the label should appear. There should also be a button for opening the settings page.
4 - Open the modal windows for changing the reward address of a visor or all visor. If you enter an invalid value on the address fiend, an error msg will appear.
5 - Go to the login page on a phone and press the language button. It should work.