Save last used swap tokens in localstorage

[p0mvn]

As requested by : we should remember the last swapped tokens the user selected on swap page so if they navigate to another page and back they would remain the same. This state is ignored if the user navigates to a swap page with query params specifying the preferred swap tokens.

[jonator]

I think we'll be tracking such things in Linear so we can add it to Cycles

[MaxMillington]

@JoseRFelix I think you fixed this right?

[jonator]

This is fixed @MaxMillington