Add hive.max-outstanding-splits-size to Hive performance tuning configuration documentation

[amir-upstream]

We had an issue with queries vs hive getting HIVE_EXCEEDED_SPLIT_BUFFERING_LIMIT (256MB)
and changing the limit through hive.max-outstanding-splits-size fixed our issue.

I believe its not so minor config and should be exposed through the documentation (I found it though the source code)

Also the word "presto" appears for the description on hive.max-splits-per-second in the official documentation which should be changed :)

[raunaqmorarka]

cc: @mosabua

[mosabua]

Good idea .. I dont know where you see the Presto mention btw @amir-upstream

@michaeleby1 can you take this on. Ping myself and @m57lyra for reference on where to best put this.

[amir-upstream]

@mosabua thx for your quick response!
here is a screenshot of the presto mention

[m57lyra]

Hi @amir-upstream - A PR got merged today that drastically reorgs the hive.rst page. It should go in the "Performance tuning configuration properties" sub section under "Performance"

[mosabua]

This was completed with the linked PR.