Token transfers will now be hidden on the ETH asset page. Arguably
token transfers are still relevant to show on the ETH asset page
because the gas for token transfers is paid in ETH, but they weren't
being displayed in a way that highlighted this (only the token amount
was shown inline - not the gas price).
We will likely restore token transfers to the ETH asset page at a later
date, after designs have been updated to highlight their relevance to
this page.
The asset page component has been split into three parts: the main
asset page wrapper, and a component for the content (either token or
native currency). This makes it easier to add functionality that is
specific to either token asset pages or native currency asset pages.
A new page has been created for viewing assets. This replaces the old
`selectedToken` state, which previously would augment the home page
to show token-specific information.
The new asset page shows the standard token overview as seen previously
on the home page, plus a history filtered to show just transactions
relevant to that token.
The actions that were available in the old token list menu have been
moved to a "Token Options" menu that mirrors the "Account Options"
menu.
The `selectedTokenAddress` state has been removed, as it is no longer
being used for anything.
`getMetaMetricState` has been renamed to `getBackgroundMetaMetricState`
because its sole purpose is extracting data from the background state
to send metrics from the background. It's not really a selector, but
it was convenient for it to use the same selectors the UI uses to
extract background data, so I left it there for now.
A new Redux store has been added to track state related to browser history.
The most recent "overview" page (i.e. the home page or the asset page) is
currently being tracked, so that actions taken from the asset page can return
the user back to the asset page when the action has finished.