frontend: transform aopp.tsx to funcitonal component

[NicolaLS]

Tested by patching the Start function in backend like this.

~~I actually forgot to remove the commit, but I guess it is good to leave it in there for reviewers to test the PR. I can remove it in the end. (note the delay is 15 seconds when testing).~~ removed it now.

I tested on webdev firefox with BB02B keystore and servewallet-mainnet. I tested the following case statements form the return: error inactive user-approval awaiting-keystore signing

I think choosing-account and syncing was tested too and looked fine but it was to fast to take a screenshot.

I think I did not test success because I don't know a callback to test aopp with.

Some pictures from testing: