Fix #280: form field focus on input on component mount

feat: Relates to #128. Add feedback button that links to Fether Github new issue

Merge into yj-focus-formfield - Don't use keycodes

feat: Relates to #311. Switch to Blockscout. Update tx link

* Switches to font size that fits a value as small as 1 Wei on the screen when more than 9 digits entered

* Switches back to default font size when amount of digits entered is 9 or less again

* Caters for when user unchecks the Max Value button

Update @parity/* packages & fix #298