feat: landing & config page UX improvements

[SgtPooki]

Title

feat: landing & config page UX improvements

Description

Fixes #58

Summary of changes

1. Add explainer with links to helper-ui (landing page)
2. Allow setting dnsResolvers in config.
3. Shows default urls in config
4. Requires at least 1 dns resolver/router/gateway
5. Adds "reset" button so users can get back to defaults if they bork things (TODO: need to fix this so it doesn't require a refresh, which will not work on first-hit for subdomain this todo is done.)

Landing page view

Config page view

Notes & open questions

FYI that inputs are still JSON based for now.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works

[SgtPooki]

self review.. i'm going to try to provide a config-provider so we can call reset/save/etc there and remove the localStorage items

[lidel]

Thanks! Content lgtm, but it felt a bit distracting, so played a bit and ended up moving it to bottom.

Pushed a commit with some additional changes:

• moved About to the bottom and made it more friendly for someone who wants to learn how things work
• adjusted colors to improve contrast and indicate when button is enabled
• tweaked the header to include (beta) and match style of other web utiities we have like https://explore.ipld.io/ or https://cid.ipfs.tech/

@SgtPooki @2color If these look good, feel free to merge or rephrase if anything sounds off.

Preview

[SgtPooki]

@lidel that looks a lot cleaner. i'll fix up the CI and get this merged.