separate generated api docs from docs.agoric.com for now

[dckc]

Fully integrating reference docs into docs.agoric.com remains a goal:

• include endo, agoric-sdk reference doc in search #927

But the current implementation has a number of issues:

• README content missing from generated typedoc #1056
• CI(integration-test): PRs in agoric-sdk should automatically trigger a verification that docs.agoric.com site still builds #1044
• etc.

So we agreed to remove them from docs.agoric.com temporarily, add sidebar entries for agoric-sdk API and endo API, and redirect them to their respective *.pages.dev counterpart.

that is:

• https://agoric-sdk.pages.dev/
• https://endojs.github.io/endo/