PowerShell Feature - Support for Alpine

Appreciate it if the PowerShell feature supported Alpine.

```
> [dev_containers_target_stage 6/6] RUN --mount=type=bind,from=dev_containers_feature_content_source,source=powershell_1,target=/tmp/build-features-src/powershell_1 cp -ar /tmp/build-features-src/powershell_1 /tmp/dev-container-features && chmod -R 0755 /tmp/dev-container-features/powershell_1 && cd /tmp/dev-container-features/powershell_1 && chmod +x ./devcontainer-features-install.sh && ./devcontainer-features-install.sh && rm -rf /tmp/dev-container-features/powershell_1:
0.341 ===========================================================================
0.341 Feature : PowerShell
0.341 Description : Installs PowerShell along with needed dependencies. Useful for base Dockerfiles that often are missing required install dependencies like gpg.
0.341 Id : ghcr.io/devcontainers/features/powershell
0.341 Version : 1.3.2
0.341 Documentation : https://github.com/devcontainers/features/tree/main/src/powershell
0.341 Options :
0.341 VERSION="latest"
0.341 MODULES=""
0.341 POWERSHELLPROFILEURL_=""
0.341 ===========================================================================
0.347 ./install.sh: line 144: dpkg: command not found
0.347 ERROR: Feature "PowerShell" (ghcr.io/devcontainers/features/powershell) failed to install! Look at the documentation at https://github.com/devcontainers/features/tree/main/src/powershell for help troubleshooting this error.
------
Dockerfile.extended:33
--------------------
32 |
33 | >>> RUN --mount=type=bind,from=dev_containers_feature_content_source,source=powershell_1,target=/tmp/build-features-src/powershell_1 \
34 | >>> cp -ar /tmp/build-features-src/powershell_1 /tmp/dev-container-features \
35 | >>> && chmod -R 0755 /tmp/dev-container-features/powershell_1 \
36 | >>> && cd /tmp/dev-container-features/powershell_1 \
37 | >>> && chmod +x ./devcontainer-features-install.sh \
38 | >>> && ./devcontainer-features-install.sh \
39 | >>> && rm -rf /tmp/dev-container-features/powershell_1
40 |
--------------------
ERROR: failed to solve: process "/bin/sh -c cp -ar /tmp/build-features-src/powershell_1 /tmp/dev-container-features && chmod -R 0755 /tmp/dev-container-features/powershell_1 && cd /tmp/dev-container-features/powershell_1 && chmod +x ./devcontainer-features-install.sh && ./devcontainer-features-install.sh && rm -rf /tmp/dev-container-features/powershell_1" did not complete successfully: exit code: 127
```

Start with the PowerShell feature's install.sh around line 144, where the Alpine build reports that dpkg is unavailable. Reproduce the failure using the Dockerfile.extended build shown in the issue and review the feature documentation linked there. Done means the PowerShell feature installs successfully on Alpine as well as its existing targets.

Scritto dal modello di indicizzazione a partire dal testo della issue.