Extension improvements

[cstrecht]

Why?

• This pull request will introduce enhancements to the Iron Wallet browser extension, improving its visual appeal, making it more organised and "easy-to-read".

Before:

At the moment:

[naps62]

@cstrecht I see what you're going for here, but a lot of these changes seem very ad-hoc, and with some consistency issues (e.g. text alignment, margins etc look inconsistent)

My idea for this was to use a data display package (the one currently used), and eventually transition to share a component library with the desktop wallet, so we could keep coherence in terms of design.
at the moment, that would mean using MUI Material as well, instead of building our own