Enable use of "standard" footer component on ENSRainbow landing page

[lightwalker-eth]

• Background info: https://namehash.slack.com/archives/C086Z6FNBHN/p1743708831170059
• Key goal: Help the footer on the ENSRainbow landing page stay in sync with the footer we use on our other landing pages in the NameKit monorepo.
• Subtasks:
  • Create a new public / shared package in the NameKit monorepo that is configured to be published to NPM.
  • Move the "standard" footer component (and its dependencies, such as icons, etc..) into the newly created public / shared package.
  • Publish that package to NPM.
  • Update ENSRainbow's landing page so that it imports the "standard" footer from NPM.
  • Remove all resources in the ENSRainbow landing page that will become redundant after the above updates.

[Y3drk]

Here is the related draft PR, in which I started the work on the issue.

[lightwalker-eth]

Note: This issue now is relevant for additional sites, including:

1. ENSRainbow.io
2. ENSNode.io
3. ENSAwards.org

[lightwalker-eth]

I think we may want to create an all new package that's managed in some all new repo for this purpose.