fix: Make `QUOTED_IDENTIFIERS_IGNORE_CASE` configurable

[ReubenFrankel]

As stated in #329, we are migrating over from an older target-snowflake and we have been running into various issues with casing; this one in particular is around tables created with quoted columns names always upper-cased (despite lower-cased in query). We have some downstream dbt models that depend on these being lower-case; something to the effect of

SELECT "start"
FROM MATATIKA_TEST.ANALYTICS,STREAM_TRELLO_CARDS

which currently results in

Error: invalid identifier 'start' (line 1)

because the target creates the table with upper-case START column, which has to be SELECTed in quotes because START is a reserved keyword:

SELECT start
FROM MATATIKA_TEST.ANALYTICS,STREAM_TRELLO_CARDS

Syntax error: unexpected 'start'. (line 1)

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Is the a reason why QUOTED_IDENTIFIERS_IGNORE_CASE set to TRUE here?

https://docs.snowflake.com/en/sql-reference/parameters#quoted-identifiers-ignore-case
https://docs.snowflake.com/en/sql-reference/identifiers-syntax#label-identifier-casing

[edgarrmondragon]

@pnadolny13 might know why, but this was done way back in a3caa38

[ReubenFrankel]

Probably goes without saying, but this would be quite a loaded change. From working on our fork, it was not as simple as removing the setting as there are also a bunch of casing modifications being made in various places.