[Mono] MSBuild Task housekeeping

[steveisok]

As discovered in #53827, we are hardcoding paths to net6.0 and net472 for MSBuild tasks that are configured to multi-target. We should instead create a template props file and generate with the tool version we have configured in runtime.

Also, while we are at it, we should create a property similar to NetCoreAppToolCurrent and use it within our tasks. NetCoreAppToolCurrent will likely bump more aggressively between new sdks and we won't really need to.

So, the issue boils down to:

• Create a property similar to NetCoreAppToolCurrent called NetCoreAppMSBuildTasksCurrent and update the tasks in src/tasks to use it.
• Create a template Sdk.props file for Microsoft.NET.Runtime.RuntimeConfigParser.Task and Microsoft.NET.Runtime.MonoAOTCompiler.Task
• Create a template Sdk.targets file for Microsoft.NET.Runtime.WebAssembly.Sdk

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Issue Details

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As discovered in #53827, we are hardcoding paths to net6.0 and net472 for MSBuild tasks that are configured to multi-target. We should instead create a template props file and generate with the tool version we have configured in runtime.

Also, while we are at it, we should create a property similar to NetCoreAppToolCurrent and use it within our tasks. NetCoreAppToolCurrent will likely bump more aggressively between new sdks and we won't really need to.

So, the issue boils down to:

• Create a property similar to NetCoreAppToolCurrent called NetCoreAppMSBuildTasksCurrent and update the tasks in src/tasks to use it.
• Create a template Sdk.props file for Microsoft.NET.Runtime.RuntimeConfigParser.Task and Microsoft.NET.Runtime.MonoAOTCompiler.Task
• Create a template Sdk.targets file for Microsoft.NET.Runtime.WebAssembly.Sdk

Author:	steveisok
Assignees:	-
Labels:	area-Infrastructure-mono
Milestone:	6.0.0

[steveisok]

/cc @lewing @akoeplinger @radical

[radical]

Create a property similar to NetCoreAppToolCurrent called NetCoreAppMSBuildTasksCurrent and update the tasks in src/tasks to use it.

NetCoreAppMSBuildTasksCurrent - this one would for the .net framework, right? Why *Current then? Naming can be discussed on the PR too.

[steveisok]

@radical Naming is always up for discussion - especially when I name things ;-)