Avalonia single project support (#9613)

* MVP SingleProject support for all supported platforms

* Convert MobileSandbox to be a single project

* WASM fixes

* Fix SDK CI version

* Use .NET 8 in build project as well

* Add EnableUnsafeBinaryFormatterSerialization

* Add macos workload, remove wasm-experimental

* And ios

* Specify TFM for single-project projects in dirs.proj

* Return deleted line

* Set PrivateAssets=all on MobileSandbox

* Add ios target only on non-linux in MobileSandbox

* Update after merges

* Update browser sub-project from the templates

* Don't build MobileSandbox on CI

* Couple of improvements

* Add android hack to run without manifest

* Add tvOS support and rearrange some properties

* Delete unusable Packages.targets file + related

* Add global Condition for AvaloniaSingleProject.targets

azure-pipelines.yml

@@ -41,7 +41,7 @@ jobs:
     displayName: 'Install Workloads'
     inputs:
       script: |
-       dotnet workload install wasm-tools wasm-experimental
+       dotnet workload install android macos wasm-tools
 
   - task: CmdLine@2
     displayName: 'Install Tizen Workload'
@@ -87,7 +87,7 @@ jobs:
     displayName: 'Install Workloads'
     inputs:
       script: |
-       dotnet workload install wasm-tools wasm-experimental
+       dotnet workload install android ios macos wasm-tools
 
   - task: CmdLine@2
     displayName: 'Install Tizen Workload'
@@ -167,7 +167,7 @@ jobs:
     displayName: 'Install Workloads'
     inputs:
       script: |
-       dotnet workload install android ios tvos wasm-tools wasm-experimental
+       dotnet workload install android ios tvos wasm-tools
 
   - task: PowerShell@2
     displayName: 'Install Tizen Workload'