[SPARK-4391][SQL] Configure parquet filters using SQLConf

[marmbrus]

This is more uniform with the rest of SQL configuration and allows it to be turned on and off without restarting the SparkContext. In this PR I also turn off filter pushdown by default due to a number of outstanding issues (in particular SPARK-4258). When those are fixed we should turn it back on by default.

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Test build #23338 has started for PR 3258 at commit 75afd39.

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Test build #23338 has finished for PR 3258 at commit 75afd39.

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Test build #23340 has started for PR 3258 at commit 15e9a98.

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Test build #23340 has finished for PR 3258 at commit 15e9a98.

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Test build #23395 has started for PR 3258 at commit 5655bfe.

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Test build #23395 has finished for PR 3258 at commit 5655bfe.

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