update project template

• let cmake set useful rpath on installation of binaries
• fix(project-template): remove extra rpath from DOOCS imported targets
• fix(project-template): cmake dev warning in FindDOOCS
• fix(project-template): imported targets for set_csa
• chore(project-template): warn about add_dependency use
• fix(project-template): for cmake 3.16 (Ubuntu 20.04)
• Increased required version of EPICS-IOC- and EPICS7-IOC-Adapter (#32)
• Enable _GLIBCXX_ASSERTIONS in Debug mode (#33)
• project-template: prepend pkgconfig for user-set DOOCS_DIR
• chore: update Python bindings helper