[Pending .NET 10] Update project templates to target upcoming .NET 10 support

[normj]

Draft Mode: This is in draft mode pending the release of .NET 10 support in Lambda.

Description of changes:

Due to the large number of files it is best to look at the changes per commit. The major changes for .NET 10 support are:

• All target framework were updated to .NET 10
• There has been a long standing usability issues when creating projects via the dotnet new command because it would always put the projects under src/<project-name> along with a test/<project-name>.Tests which at this point is probably rarely needed. This rigid structured made it hard to easily add a new Lambda project into an existing workspace because it probably had it's own structure. Commit XXXX changed the templates so that there is no longer a test project and the code for the Lambda project will be created in the exact output folder.
• .NET 10 added support C# file-based applications. In PR XXX of Amazon.Lambda.Tools is support for deploying C# file-based apps as Lambda functions. The new lambda.FileBased template create a C# file with all of the necessary boiler plate for creating a Lambda function.
• Updated all the package references

Breakdown of commits:

• d5ee2dc - Simple copy of all the content from vs2022 to vs2026. This causing the build of the files and can be ignored.
• 9363938 - Big string replace for .NET 10 target framework and .NET 10 Lambda managed runtime
• 3b6c7c4 - Started the change file
• 3777829 - Moved the .template.config folder to the src/<blueprint> folder and corrected paths in the config file. This is what address the usability
• a52359a - Add the new C# file-based template
• fb3a9e9 - Update the packager used for converting the templates for the AWS Toolkit for Visual Studio to not include C# file-based templates as well as not include the .template.config folder now that it was moved into the source folder
• 3fe4884 - Use the blueprint packager's command to update all of the packagereferences to the latest versions.
• f7b066c - Update build targets to test instantiating and building the new VS2026 templates. Address build and compiler warnings.
  • During the packagereference commit the amazon packages are updated automatically but I also manually updated the test packages. I incorrectly updated xunit.runner.visualstudio to 3.15 when it should have been 3.1.5.
  • There were warnings in the F# projects for using the obsolete WebHost. I updated to use the newer APIs.
• 5eb708e - Update change file to call out the new the C# file-based blueprint
• 29a2a8b - For the ASP.NET Core Web App template updated the static content in the wwwroot folder with the latest content you get when you create a new ASP.NET Core Web App in VS
• 6355a64 - When I updated the build.proj to test the templates I took out msbuild target dependencies to speed up build turnaround. That was not meant to be checked in and was reverted in this commit.
• 3b95213 - I manually updated the version Amazon.Lambda.Templates NuGet package to test locally and accidently checked it in. This commit reverts that change.
• da52a25 -Update container images to use public.ecr.aws/lambda/dotnet:10 as the base image.
  By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.