Improve progress output, rebuild project serially

[tmat]

Only capture output of dotnet build when running in a test environment. In production, let dotnet build show build progress.

Output messages that inform of project evaluation start and end, and project load start and end, and include elapsed time.
Output "Waiting for changes" even when --verbose is not specified, so that it's clear when dotnet-watch starts to listen for changes.

When projects need to be rebuilt due to rude edits, rebuild them serially to avoid potential write access issues of dependent project outputs.

[github-actions]

This PR is targeting main, which is now for .NET 11-facing work. If you intended to target .NET 10, either retarget this PR to release/10.0.1xx or make sure you backport the change to release/10.0.1xx after merging. See #50394 for more details.