watson: add module

Watson is a CLI for tracking your time.

Two unit tests were added to validate the module behavior for an empty
configuration and the example configuration.

tests/modules/programs/watson/example-settings-expected.ini

@@ -0,0 +1,14 @@
+[backend]
+token=yourapitoken
+url=https://api.crick.fr
+
+[options]
+date_format=%Y.%m.%d
+log_current=false
+pager=true
+report_current=false
+reverse_log=true
+stop_on_restart=false
+stop_on_start=true
+time_format=%H:%M:%S%z
+week_start=monday