Provide CI builds of Positron Server for Linux

[jmcphers]

Currently our CI release builds only include macOS desktop builds, e.g.:

https://github.com/posit-dev/positron/releases/tag/2023.10.0-1269

We should start building Linux releases of Positron, too, starting with Positron Server; this is a prerequisite to including Positron inside Posit Workbench.

[jmcphers]

Needed for RC since it's needed for Workbench

[sharon-wang]

TODOs

• https://github.com/posit-dev/positron/issues/4379
  • [x] Run local debug build successfully
• https://github.com/posit-dev/positron/pull/4426
  • [x] Run local release build successfully (yes with caveats -- see extensions issue below)
  • [x] Build CI release build successfully
  • [x] Run CI release build successfully (yes with caveats -- see extensions issue below)
  • [x] Add handling for auto-merging remote and web dependencies https://github.com/posit-dev/positron/pull/4473
  • [x] At least pyright and quarto extensions (probably all extensions) are erroring with a notification toast on startup with No valid VS Code version detected: Version string is: 2024.08.0
• opened separate issue https://github.com/posit-dev/positron/issues/4479
  • Update resources/server/favicon.ico for Positron (maybe we can add to positron-product-icons/update-icons.sh to generate the ico file?)

[sharon-wang]

For verification

Relevant PRs:

• https://github.com/posit-dev/positron/pull/4426
• https://github.com/posit-dev/positron-builds/pull/49

There's a linux build PR has steps on how to run the build. Please reach out to me if I can clarify anything!

[testlabauto]

Verified Fixed

Positron Version(s) : Positron Build: Daily Release #61
OS Version          : Ubuntu

Test scenario(s)

Verified with instructions here: https://github.com/posit-dev/positron-builds/pull/49

Link(s) to TestRail test cases run or created: N/A