Firmware loader usability improvement

[kobelev-tech]

Modify the window of the first step:

1. Add the message as on the screenshot above. It should be in a big enough font be and bold.
2. Rename the button into "Next".

Modify the window of the second step:

1. Replace the message on top with "Check the progress, once ready press save" or remove this message at all.
2. Remove the "Program" button. In any case it is not doing anything.

Optional: If waiting for the comport state stays longer than 10 seconds, show recommendation to reconnect. This recommendation should not be present on the screen at the beginning. User will miss it.

[dlktdr]

I also need to add if the flash fails suggest that the user double tap reset after connecting the board to force bootloader. Maybe a link to the online docs on flashing issues as well.