Update Prepare-Release.ps1 to support rust libraries

[ronniegeraghty]

Update the /eng/common/scripts/Prepare-Release.ps1 script to support rust libraries.

Required before this work can start:

• Add rust release pipelines #1868

[hallipr]

Prepare-Release left language specific dependencies to LanguageSettings.ps1

The changes to support Prepare-Release were added with #2032.
Prepare-Release.ps1 should be working for Rust now.