Workloads not working for 10.0.2xx branch

[marcpopMSFT]

For the admin installs, the workload manifests getting installed are not what we want. This will eventually lead to conflicts with the 10.0.100 branch when 10.0.200 goes stable (or duplicates but with higher versions). I don't know if it'll cause issues for anyone installing the daily builds.
microsoft.net.workload.mono.toolchain.current": "10.0.200-preview.0.25528.101/10.0.100-preview.0",

For non-admin builds, it's actually putting them in a stable feature band location. This will potentially cause issues with SxS SDKs:
"microsoft.net.workload.mono.toolchain.current": "10.0.200-preview.0.25530.103/10.0.100",

Options

1. 2xx pulls in the 1xx workload msis and content
2. Move workload manifest generation back to runtime/emsdk repo
3. 2xx pulls in the 1xx workload msis only. Non-admin builds get some 2xx version
4. 2xx builds specially versioned baseline manifests that are always below 10.0.100 for fallback and msi install.

Proposal 4

• Install baseline manifests to a folder of this structure: 10.0.100-baseline\microsoft.net.workload.emscripten.current\10.0.200-preview.0.25530.103
• If a stable build is installed SxS, I've confirmed that it'll use that instead.
  • "microsoft.net.workload.mono.toolchain.current": "10.0.100/10.0.100",
• If no stable build is installed, it'll see the baseline workloads
  • "microsoft.net.workload.mono.toolchain.current": "10.0.200-preview.0.25530.103/10.0.100-baseline",
• Two different previews can be installed SxS as they go into different sub-folders of the 10.0.100-baseline folder.
• If installing from a workload set
  _- Installing workload version 10.0.200-preview.0.25530.1
  • Installing workload manifest microsoft.net.workload.mono.toolchain.current version 10.0.100...
  • Successfully updated workload(s)_
• If installing from loose manifests
  • It looks for microsoft.net.workload.mono.toolchain.net8.manifest-10.0.100-baseline which doesn't exist <-- this is the hack we'd need.