Update build infrastructure

Review Dockerfile and third-party dependencies

• libssh2 1.9.0 (remember to build with cmake to get cmake config files)
• boost 1.75
• cmake 3.20
• devtoolset-9
• cppzmq 4.7.1, build and install
• git224 from https://ius.io/ (and uninstall git from centos, too old for vscode)