Update for Stardew Valley 1.3.33 and SMAPI 3.0, fix crossplatform compatibility

[Pathoschild]

This pull request...

• Adds compatibility with Stardew Valley 1.3.33 and SMAPI 3.0 (still compatible with SMAPI 2.10).
• Reworks Harmony patching for crossplatform compatibility.*
• Migrates to the new package reference format.
• Updates the mod build config package and migrates to the new Harmony package.
• Simplifies the project file using the mod build config features (e.g. i18n and manifest.json files are copied automatically).
• Bumps the manifest.json versions for release.
• Fixes various errors reported by users.

_{* (SMAPI automatically handles code changes between Linux/Mac and Windows, but it can't do that for type references in attributes. Using Harmony's API instead means the mod will work seamlessly across Linux/Mac/Windows without needing separate builds.)}

Let me know if you want me to make any changes!

[Pathoschild]

Superceded by PR #3.