Build packages with Ubuntu 18.04

Restores Ubuntu 18.04 packages
Update docker images to use Conan

Builds/CMake/RippledCompiler.cmake

@@ -124,7 +124,10 @@ else ()
       #   * static option set and
       #   * NOT APPLE (AppleClang does not support static libc/c++) and
       #   * NOT san (sanitizers typically don't work with static libc/c++)
-      $<$<AND:$<BOOL:${static}>,$<NOT:$<BOOL:${APPLE}>>,$<NOT:$<BOOL:${san}>>>:-static-libstdc++>)
+      $<$<AND:$<BOOL:${static}>,$<NOT:$<BOOL:${APPLE}>>,$<NOT:$<BOOL:${san}>>>:
+      -static-libstdc++
+      -static-libgcc
+      >)
 endif ()
 
 if (use_gold AND is_gcc)