statistics: opened vs. closed issue counts

[csonuryilmaz]

For a given redmine project and time period, it will output opened vs. closed issue counts.

Example:
(parameters)
PROJECT = Support
DATE_BETWEEN= 2017-01-01,2017-01-31
(output)
opened;closed
32;22

Notes:

• Output is in CSV format. (Default field separator is semicolon.)
• First row in output is field names.
• Date between parameter is inclusive. (From start date 00:00:00 to end date 23:59:59)