MXS-2310: Document and install cdc_one_schema.py

Added documentation for the script and installed it as a part of the
default package.

Documentation/Routers/Avrorouter.md

@@ -306,6 +306,47 @@ If the CREATE TABLE statements for the tables aren't present in the current
 binary logs, the schema files must be generated with a schema file
 generator. There are currently two methods to generate the .avsc schema files.
 
+### Simple Schema Generator
+
+The `cdc_one_schema.py` generates a schema file for a single table by reading a
+tab separated list of field and type names from the standard input. This is the
+recommended schema generation tool as it does not directly communicate with the
+database thus making it more flexible.
+
+The only requirement to run the script is that a Python interpreter is
+installed.
+
+To use this script, pipe the output of the `mysql` command line into the
+`cdc_one_schema.py` script:
+
+```
+mysql -ss -u <user> -p -h <host> -P <port> -e 'DESCRIBE `<database>`.`<table>`'|./cdc_one_schema.py <database> <table>
+```
+
+Replace the `<user>`, `<host>`, `<port>`, `<database>` and `<table>` with
+appropriate values and run the command. Note that the `-ss` parameter is
+mandatory as that will generate the tab separated output instead of the default
+pretty-printed output.
+
+An .avsc file named after the database and table name will be generated in the
+current working directory. Copy this file to the location pointed by the
+`avrodir` parameter of the avrorouter.
+
+Alternatively, you can also copy the output of the `mysql` command to a file and
+feed it into the script if you cannot execute the SQL command directly:
+
+```
+# On the database server
+mysql -ss -u <user> -p -h <host> -P <port> -e 'DESCRIBE `<database>`.`<table>`' > schema.tsv
+# On the MaxScale server
+./cdc_one_schema.py <database> <table> < schema.tsv
+```
+
+If you want to use a specific Python interpreter instead of the one found in the
+search path, you can modify the first line of the script from `#!/usr/bin/env
+python` to `#!/path/to/python` where `/path/to/python` is the absolute path to
+the Python interpreter (both Python 2 and Python 3 can be used).
+
 ### Python Schema Generator
 
 ```

server/modules/protocol/examples/CMakeLists.txt

@@ -3,4 +3,5 @@ install_script(cdc_users.py core)
 install_script(cdc_last_transaction.py core)
 install_script(cdc_kafka_producer.py core)
 install_script(cdc_schema.py core)
+install_script(cdc_one_schema.py core)
 install_file(cdc_schema.go core)