Add js libs

[Kevingislason]

Description

see also https://github.com/Manta-Network/manta-js/pull/22

Move the end to end test pipeline plus relevant libraries from manta-js to this repo. Most files are simply moved from there unchanged, with a few exceptions:

-Tweaked the release pipeline to cache files based on matrix.os instead of runner.os. This was inconsistently causing one of the Ubuntu builds to fails. cc @tommyjk21
-Changed simulator code to avoid zero-value private transfers, which the runtime doesn't allow cc @bhgomes
-Moved simulator directory into e2e. It seems like the simulator "belongs to" the end to end test, and it's strange to have a rust package at the top level of the js folder. In any case, I think this is getting replaced soon. cc @bhgomes

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Linked to Github issue with discussion and accepted design OR have an explanation in the PR that describes this work.
• [n/a] Test following procedure in docs/testing-workflow.md
• Updated relevant documentation in the code.
• Re-reviewed Files changed in the Github PR explorer.
• [n/a] Update the version numbers properly:
  • Cargo.toml
  • ui/src-tauri/Cargo.toml
  • ui/src-tauri/tauri.conf.json
  • ui/public/about.html
  • ui/package.json

[tjsharp1]

👍