feat(extension): onboarding frontends selection

[VanishMax]

Closes #1230

The idea is the following:

1. Remove the hard-coded MINIFRONT_URL constant, use Prax registry to import the frontend options instead
2. Show a new onboarding screen for default frontend selection. The options are taken from the frontends field in the Prax registry plus an RPC field from the previous onboarding step. Also, a custom URL can be set and stored per the session
3. Reuse this onboarding screen for the same-named settings page
4. A redirect from the "manage portfolio" button to the settings page in case users don't have a frontend selected

https://github.com/penumbra-zone/web/assets/29180358/a7d0fc2c-4859-4252-9388-0e5eef432bd0

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 0dbda4e53348ec951982c483e732e03f3fa461b8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 7 packages

| Name | Type | | ------------------------------- | ----- | | @penumbra-zone/storage | Minor | | chrome-extension | Minor | | @penumbra-zone/ui | Patch | | @penumbra-zone/services-context | Patch | | @penumbra-zone/services | Patch | | minifront | Patch | | node-status | Patch |

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[VanishMax]

Thanks @Valentine1898 and @grod220 for the comments. I improved the designs and logic of this feature according to your comments. Updated the video in the PR description, so you can check how it works now

[VanishMax]

@grod220 Thanks for the proposals, I implemented them all. Merging soon