Implement per-test timeout guard

Timeout value can be specified by test in suite.conf:

config:
  suite:
    <suite_name>:
      <test_name>:
        timeout: 2 # 2 seconds timeout

Change-Id: I522f51f77f8be64ebfdb5d5e07ba92baf82d7706
diff --git a/doc/manuals/chapters/config.adoc b/doc/manuals/chapters/config.adoc
index 118f056..f4e08b3 100644
--- a/doc/manuals/chapters/config.adoc
+++ b/doc/manuals/chapters/config.adoc
@@ -190,7 +190,18 @@
   a_suite_test_foo:
     one_test_parameter_for_test_foo: 'str'
     another_test_parameter_for_test_foo: ['bool_str']
+
+config:
+  suite:
+    <suite_name>:
+      some_suite_parameter: 3
+      a_suite_test_foo:
+        one_test_parameter_for_test_foo: 'hello'
+        timeout: 30 <1>
 ----
+<1> The per-test _timeout_ attribute is implicitly defined for all tests with
+type _duration_, and will trigger a timeout if test doesn't finish in time
+specified.
 
 [[scenarios_dir]]
 ==== 'scenarios_dir'