Add Date Processor Plugin (#5895)

plugins/processors/date/README.md

@@ -0,0 +1,31 @@
+# Date Processor Plugin
+
+The `date` processor adds the months and years as tags to your data.
+
+Provides the ability to group by months or years. 
+
+A few example usecases include: 
+1) consumption data for utilities on per month basis 
+2) bandwith capacity per month
+3) compare energy production or sales on a yearly or monthly basis 
+
+
+### Configuration:
+
+```toml
+[[processors.date]]
+  ##Specify the date tags to add rename operation.
+  tagKey = "month"
+  dateFormat = "Jan"
+```
+
+### Tags:
+
+Tags are applied by this processor. 
+
+### Example processing:
+
+```
+- throughput, hostname=example.com lower=10i,upper=1000i,mean=500i 1502489900000000000
++ throughput,host=backend.example.com,month=Mar min=10i,max=1000i,mean=500i 1502489900000000000
+```