[embetten]

For #621

In 2.0.0 we updated the install scripts to default to the self-contained version if we were able to detect a supported runtime and architecture. If a non-supported os and architechture, we would default to the non self-contained version. For linux, This change did not take linux musl into account - which would require shipping supported self-contained versions linux-musl-x64 and linux-musl-arm64 where we are only shipping linux-x64 and linux-arm64.

This proposed change attempts to detect if a linux machine uses musl instead of glibc, and if true, treat it like a non-supported platform and install the non self-contained netcore version.

sample dockerfile on alpine with successful build for his branch

FROM mcr.microsoft.com/dotnet/sdk:8.0-alpine AS build-env

## dont use this script directly outside of testing this pr branch
RUN wget -qO- https://raw.githubusercontent.com/microsoft/artifacts-credprovider/refs/heads/users/embetten/musl-detection/helpers/installcredprovider.sh | sh

ARG FEED_URL
ARG FEED_ACCESSTOKEN

# Optional: Sometimes the http client hangs because of a .NET issue. Setting this in dockerfile helps 
ENV DOTNET_SYSTEM_NET_HTTP_USESOCKETSHTTPHANDLER=0
ENV VSS_NUGET_EXTERNAL_FEED_ENDPOINTS="{\"endpointCredentials\": [{\"endpoint\":\"$FEED_URL\",\"username\":\"docker\",\"password\":\"$FEED_ACCESSTOKEN\"}]}"

WORKDIR /app

RUN dotnet new console
RUN dotnet new nugetconfig
RUN dotnet nuget remove source nuget
RUN dotnet nuget add source $FEED_URL -n embettenTest --configfile ./nuget.config
RUN dotnet add package Microsoft.Identity.Client.Extensions.Msal --version 4.77.1
RUN dotnet restore --verbosity detailed