Support using dev.webui.ipfs.io as webui

[lidel]

Right now, opt-in is not very user friendly, and it works only with webui.ipfs.io, which is latest release

To make testing easier, we should

• replace toggle with select that has 3 options:
  • webui.ipfs.io (latest release from https://github.com/ipfs-shipyard/ipfs-webui/releases/)
  • dev.webui.ipfs.io (latest commit from main branch in https://github.com/ipfs-shipyard/ipfs-webui/pulls/_
• (optional) set proper CORS based on the choice (worth doing only if applied immediately, if it requires restart, no point in doing this)