Add TriggerManager and Trigger objects

Implemented initial version of Trigger and TriggerManager DBus
interfaces. Now DBus user is able to add new Trigger and delete it.
There is no support for other functionality added.

Tested:
 - Built using yocto dependencies with success
 - Unit tests passed
 - Verified manually if Trigger and TriggerManager works as
   expected

Change-Id: Ie68463526ecccc3be67cc7bfaaf9a9aa7326dee6
Signed-off-by: Wludzik, Jozef <jozef.wludzik@intel.com>
diff --git a/meson.build b/meson.build
index 160946f..c40b9f3 100644
--- a/meson.build
+++ b/meson.build
@@ -72,6 +72,7 @@
     '-DTELEMETRY_MAX_REPORTS=' + get_option('max-reports').to_string(),
     '-DTELEMETRY_MAX_READING_PARAMS=' + get_option('max-reading-parameters').to_string(),
     '-DTELEMETRY_MIN_INTERVAL=' + get_option('min-interval').to_string(),
+    '-DTELEMETRY_MAX_TRIGGERS=' + get_option('max-triggers').to_string(),
     language: 'cpp'
 )
 
@@ -86,6 +87,9 @@
         'src/report_manager.cpp',
         'src/sensor.cpp',
         'src/sensor_cache.cpp',
+        'src/trigger.cpp',
+        'src/trigger_factory.cpp',
+        'src/trigger_manager.cpp',
     ],
     dependencies: [
         boost,