WT-13410: Switch Boost archive URL

JFrog is no longer offering webspace to Boost. They used to do this, but
this is costing them a lot. Boost now offers their own in-house URL to
download archives.

See:
- boostorg/boost#843 (comment)
- boostorg/website#900

P.S. while this isn't breaking for the builds, as this is cached. This
can result in breaking builds later, if the Dockerfile were to change.

jenkins/linux/minimal.Dockerfile

@@ -28,7 +28,7 @@ RUN apt-get update && apt-get install --no-install-recommends -y \
 
 RUN BOOST_VERSION=1.71.0 ;\
     BOOSTDIR=boost_${BOOST_VERSION//[.]/_} ;\
-    wget https://boostorg.jfrog.io/artifactory/main/release/${BOOST_VERSION}/source/${BOOSTDIR}.tar.bz2 -O ${BOOSTDIR}.tar.bz2 \
+    wget https://archives.boost.io/release/${BOOST_VERSION}/source/${BOOSTDIR}.tar.bz2 -O ${BOOSTDIR}.tar.bz2 \
  && tar xf ${BOOSTDIR}.tar.bz2 \
  && rm ${BOOSTDIR}.tar.bz2 \
  && (cd ${BOOSTDIR} \