Hardcode favicon URLs for DefaultSuggestediStes and remove old code for using bundled favicon assets

[data-sync-user]

• Delete the hardcoded bundled favicon images (many of which are outdated)
• Delete code that loads these images from the bundle
• Overall simplify the favicon-related code as much as possible
• Delete Tippy Top Sites JSON (won’t be needed anymore)
• Hard code the DefaultSuggestedSites with the correct favicon URLs to speed up showing the top sites on first launch

┆Issue is synchronized with this Jira Task

[data-sync-user]

➤ ih-codes commented:

I’m going to consider this blocked by https://mozilla-hub.atlassian.net/browse/FXIOS-9745 ( https://mozilla-hub.atlassian.net/browse/FXIOS-9745|smart-link ) because the issue will be exacerbated by my changes.