v2.0-0: Cgroups v2 now supported!

• add support for "cpu" and "memory" cgroup controllers v2
• bump major version of cmonitor_collector and cmonitor_tools from 1.8-5 to 2.0-0
• add new data collected from kernel of Fedora35
• backward incompat change: change cgroups v1 memory stats replacing the "total_" prefix with "stat." to make them more similar to cgroups v2 stats
• add major version check in cmonitor_chart and cmonitor_statistics to avoid troubles when mixing by mistake recordings obtained with version 1.8-5 and version 2.0-0
• regenerate all examples