Caliper-plugin QOL improvement
Add missing config documentation for Caliper service

- If a subSampling value of 0 or lower is chosen for a sensor, it will
never be pushed out over MQTT/Cassandra and only kept in memory

- Make clean might be required

- This plugin allows to write arbitrary sensor data to the local file system
- Removed the obsolete sink functionality in SensorBase
- Also fixed a minor bug concerning MQTT topic assignment in template analyzers

- The MQTT topic of a sensor is now used to identify the file name of the
sink and is appended to the path given as input

- Update config files to reflect new topic structure
- Updated READMEs accordingly
- Added support for "relaxed" analyzers, whose units can be built
even if some sensors cannot be found in the system
- Added support for sub-units, so as to build hierarchical unit structures

CollectAgent should be switched to new Rest API design as soon as possible
Minor improvements to README, Makefile and PUT /analytics/reload methods

- Fixed name of log files for collectagent
- Fixed a few compilation warnings under gcc 7
- README for dcdbpusher now correctly refers to dcdbpusher.conf files
- SensorNavigator is rebuilt after plugin reloads only if data analytics
are currently running

Change perf-plugin implementation: Instead of duplicating sensorGroups per CPU only one group is used with duplicated sensors