Separating the installation of configuration files from binaries/libs, otherwise they get overwritten with make install

- Now the percentages are computed based from the delta of each column
with respect to the last reading
- ProcstatPercParser renamed to SARParser for clarity
- New corresponding sensor group type is "sar"

- Sensors now support a "delta" field in config files. If set to "on",
differences between successive readings instead of the raw values will
be stored
- Default is "off"
- This option should only be applied to monotonic sensors
- Can be applied to perfevents as well

- At starting time, the actual MQTT message rate across all plugins is
computed and compared with the maxNumberOfMessages parameter
- If the latter is less than the former, the setting is ignored and no
message cap is imposed
- This prevents situations in which a low cap prevents readings
for some sensors from being sent, leading to missing data and potential
memory leaks
- The check is repeated any time the sensor config changes

- Now all sensors across all plugins adopt the naming convention
cpu<CPUid>.<sensorName>, if CPU-related, or just <sensorname> otherwise
- Code to parse cpu sets used both in Perfevent and ProcFS plugins
moved up in ConfiguratorTemplate
- Misc code to format MQTT parts also moved up in ConfiguratorTemplate

- This commit reflects changes made in the master branch and should
make the eventual merge less painful