docs: adding skeleton README.md files for all vlib modules (#13034)

vlib/time/README.md

@@ -0,0 +1,17 @@
+## Description:
+
+`time` provides utilities for working with time and dates:
+- parsing of time values expressed in one of the commonly used standard time/date formats
+- formatting of time values
+- arithmetic over times/durations
+- converting between local time and UTC (timezone support)
+- stop watches for accurately measuring time durations
+- sleeping for a period of time
+
+## Examples:
+
+```v
+import time
+
+println(time.now())
+```