docker: Compile own openssl for steamrt builds

Steam's scout image provides way too old openssl library version which doesn't
doesn't properly handle recent expiry of one of root Let's Encrypt
certs.

utils/dockerbuilds/CI/Dockerfile-base-steamrt

@@ -10,4 +10,8 @@ RUN wget --max-redirect 3 https://boostorg.jfrog.io/artifactory/main/release/$BO
 RUN mkdir -p /src/boost && tar zxf boost_${BOOST_VERSION_}.tar.gz -C /src/boost --strip-components=1
 RUN cd /src/boost && ./bootstrap.sh --with-libraries=iostreams,regex,system,filesystem,program_options,random,locale,context,coroutine && ./b2 toolset=gcc-9 --layout=system link=static variant=release cxxflags='-fPIE -fstack-protector-strong' define=_FORTIFY_SOURCE=2 install
 
-RUN mkdir -p /staging/lib64 && cp /usr/lib/libicu*.so.* /lib/x86_64-linux-gnu/libhistory.so.6 /lib/x86_64-linux-gnu/libcrypto.so.1.0.0 /lib/x86_64-linux-gnu/libssl.so.1.0.0 /staging/lib64/
+RUN wget https://www.openssl.org/source/openssl-1.1.1l.tar.gz --no-check-certificate
+RUN mkdir -p /src/openssl && tar zxf openssl-1.1.1l.tar.gz -C /src/openssl --strip-components=1
+RUN cd /src/openssl && ./config --prefix=/usr/local --openssldir=/etc/ssl && make && make install
+
+RUN mkdir -p /staging/lib64 && cp /usr/lib/libicu*.so.* /lib/x86_64-linux-gnu/libhistory.so.6 /usr/local/lib/libcrypto.so.1.1 /usr/local/lib/libssl.so.1.1 /staging/lib64/