Add dappkit-web functionality

[eelanagaraj]

Want to get some initial feedback since there was a lot of discussion on how we want to structure the separate modules.

• In this PR, there are a few functions that now have web-specific counterparts(waitForAccountAuthWeb, waitForSignedTxsWeb, parseURLOnRender).
• I implemented these in a decorator-like style, so refactored the mobile functions in the process (and haven't published/tested these yet), but we can always remove the majority of the mobile changes if need be.
• I didn't create counterparts for listenToAccount or listenToSignedTxs -- it seems like we never use these in the tutorials/docs anyways (maybe it makes sense to deprecate these?? the functionality is very very similar to the waitFor* functions except for not requiring a requestId)

(web mods heavily based on Alex's workaround in use-contractkit
(- Includes Alex's change from Expo -> react-native (can rebase again once that is pushed to devx/update-dappkit))

Closes #7348

[AlexBHarley]

Looks good! I think this is a better direction to be taking (separate implementations for web and react-native).

I'd prefer we move the web package into its own file rather than suffixing functions with *Web. That way we could just do import {waitForAccountAuth} from '@celo/dappkit/web.

It also probably makes sense for there to be a timeout on the polling action? If not, at least we should provide a way to cancel polling. Reading LocalStorage every 100ms until someone refreshes their isn't terrible but not ideal either.

[eelanagaraj]

@AlexBHarley split into two files for now but without any special nesting/configuration--was playing around with this a bit but it felt messy to have nested tsconfigs and wasn't working as cleanly as I'd hoped, so for now web imports would look like import {...} from @dappkit/lib/web. Also export all of the same crossover functions in dappkit-web to allow for users to just import one vs. the other (even for shared functions).

Added a simple timeout for now, but yeah I think canceling dappkit flows would be a nice feature (and has a different ticket out for it?) will continue thinking about how that could look!

[AlexBHarley]

This looks good to me!