Trim unused/duplicate build artifacts

[runesoerensen]

We currently don't do anything to clean up intermediate build artifacts following a build. However, running dotnet publish produces several unused build artifacts that are copied/duplicated to the bin/publish folders users will use.

In many cases this has a relatively small impact on the output footprint. However, the impact can be quite significant in certain cases -- especially when the source includes large files that are copied to the output directory, or when compiling self-contained and/or AOT apps.

The number of unused/duplicated files can be reduced by setting the artifacts path property during the build. Setting the artifacts path to a /tmp/foo folder, in combination with the PublishDir msbuild property, effectively eliminates most of the duplication.

Users can already configure this by including a Directory.Build.props file similar to this:

<Project>
  <PropertyGroup>
    <ArtifactsPath>/tmp/dotnetartifacts</ArtifactsPath>
  </PropertyGroup>
</Project>

The difference in disk usage (with and without artifacts path configured to a tmp directory) can be seen for a couple template webapiaot and blazor apps below.

We may want to consider setting the artifacts path by default for all builds (by setting the --artifacts-path parameter during dotnet publish).

Web API AOT app (`webapiaot` template)
================================

Workspace disk usage (without artifacts path set to tmp directory)
------------------------------------------------------------------

heroku@799072c54d1d:/workspace$ du -h
30M    ./bin/publish
30M    ./bin/Release/net9.0/linux-arm64/native
140M   ./bin/Release/net9.0/linux-arm64
140M   ./bin/Release/net9.0
140M   ./bin/Release
170M   ./bin
8.0K   ./Properties
16K    ./obj/Release/net9.0/linux-arm64/staticwebassets
50M    ./obj/Release/net9.0/linux-arm64/native
16K    ./obj/Release/net9.0/linux-arm64/refint
16K    ./obj/Release/net9.0/linux-arm64/ref
50M    ./obj/Release/net9.0/linux-arm64
50M    ./obj/Release/net9.0
50M    ./obj/Release
51M    ./obj
220M   .


Workspace disk usage (with artifacts path set to tmp directory)
---------------------------------------------------------------

heroku@b923600529ec:/workspace$ du -h
30M    ./bin/publish
30M    ./bin
8.0K   ./Properties
28K    ./obj
30M    .


Blazor template app (`blazor` template)
===================

Workspace disk usage (without artifacts path set to tmp directory)
------------------------------------------------------------------

heroku@1ede41998606:/workspace$ du -h
7.6M   ./bin/publish/wwwroot/lib/bootstrap/dist/css
3.5M   ./bin/publish/wwwroot/lib/bootstrap/dist/js
12M    ./bin/publish/wwwroot/lib/bootstrap/dist
12M    ./bin/publish/wwwroot/lib/bootstrap
12M    ./bin/publish/wwwroot/lib
12M    ./bin/publish/wwwroot
12M    ./bin/publish
512K   ./bin/Release/net9.0/linux-arm64
516K   ./bin/Release/net9.0
520K   ./bin/Release
13M    ./bin
8.0K   ./Properties
20K    ./Components/Pages
20K    ./Components/Layout
56K    ./Components
6.0M   ./wwwroot/lib/bootstrap/dist/css
2.5M   ./wwwroot/lib/bootstrap/dist/js
8.4M   ./wwwroot/lib/bootstrap/dist
8.4M   ./wwwroot/lib/bootstrap
8.4M   ./wwwroot/lib
8.4M   ./wwwroot
1.2M   ./obj/Release/net9.0/linux-arm64/compressed/publish
2.8M   ./obj/Release/net9.0/linux-arm64/compressed
156K   ./obj/Release/net9.0/linux-arm64/staticwebassets
12K    ./obj/Release/net9.0/linux-arm64/refint
12K    ./obj/Release/net9.0/linux-arm64/ref
12K    ./obj/Release/net9.0/linux-arm64/scopedcss/Components/Layout
16K    ./obj/Release/net9.0/linux-arm64/scopedcss/Components
12K    ./obj/Release/net9.0/linux-arm64/scopedcss/projectbundle
12K    ./obj/Release/net9.0/linux-arm64/scopedcss/bundle
44K    ./obj/Release/net9.0/linux-arm64/scopedcss
5.3M   ./obj/Release/net9.0/linux-arm64
5.3M   ./obj/Release/net9.0
5.3M   ./obj/Release
5.3M   ./obj
27M    .

Workspace disk usage (with artifacts path set to tmp directory)
---------------------------------------------------------------

heroku@785c48fba042:/workspace$ du -h
7.6M   ./bin/publish/wwwroot/lib/bootstrap/dist/css
3.5M   ./bin/publish/wwwroot/lib/bootstrap/dist/js
12M    ./bin/publish/wwwroot/lib/bootstrap/dist
12M    ./bin/publish/wwwroot/lib/bootstrap
12M    ./bin/publish/wwwroot/lib
12M    ./bin/publish/wwwroot
12M    ./bin/publish
12M    ./bin
8.0K   ./Properties
20K    ./Components/Pages
20K    ./Components/Layout
56K    ./Components
6.0M   ./wwwroot/lib/bootstrap/dist/css
2.5M   ./wwwroot/lib/bootstrap/dist/js
8.4M   ./wwwroot/lib/bootstrap/dist
8.4M   ./wwwroot/lib/bootstrap
8.4M   ./wwwroot/lib
8.4M   ./wwwroot
21M    .