Fixed a problem with sqlserver input where database properties are not returned by Telegraf when SQL Server has been set up with a case sensitive server-level collation.

* Added bugfix entry to CHANGELOG.md for sqlserver collation input fix.

Issue #1854

I added Rows/Logs max size counters for tracking databases that do not have autogrowth enabled. The counters return numbers in 8KB pages since there are a few special values (such as -1 for no max size) that can't directly be multiplied by 8192 to get size in bytes.

Also added Rows/Logs size in 8KB pages for comparison from the same system table. Even though it returns the same size as sizes from sys.dm_io_virtual_file_stats which are already collected.

This will basically make the root directory a place for storing the
major telegraf interfaces, which will make telegraf's godoc looks quite
a bit nicer. And make it easier for contributors to lookup the few data
types that they actually care about.

closes #564

closes #589