Concurrent CSV parsing and reduce S3 select allocations (minio#8200)

```
CSV parsing, BEFORE:
BenchmarkReaderBasic-12         	    2842	    407533 ns/op	  397860 B/op	     957 allocs/op
BenchmarkReaderReplace-12       	    2718	    429914 ns/op	  397844 B/op	     957 allocs/op
BenchmarkReaderReplaceTwo-12    	    2718	    435556 ns/op	  397855 B/op	     957 allocs/op
BenchmarkAggregateCount_100K-12    	     171	   6798974 ns/op	16667102 B/op	  308077 allocs/op
BenchmarkAggregateCount_1M-12    	      19	  65657411 ns/op	168057743 B/op	 3146610 allocs/op
BenchmarkSelectAll_10M-12    	       1	20882119900 ns/op	2758799896 B/op	41978762 allocs/op

CSV parsing, AFTER:
BenchmarkReaderBasic-12         	    3721	    312549 ns/op	  101920 B/op	     338 allocs/op
BenchmarkReaderReplace-12       	    3776	    318810 ns/op	  101993 B/op	     340 allocs/op
BenchmarkReaderReplaceTwo-12    	    3610	    330967 ns/op	  102012 B/op	     341 allocs/op
BenchmarkAggregateCount_100K-12    	     295	   4149588 ns/op	 3553623 B/op	  103261 allocs/op
BenchmarkAggregateCount_1M-12    	      30	  37746503 ns/op	33827931 B/op	 1049435 allocs/op
BenchmarkSelectAll_10M-12    	       1	17608495800 ns/op	1416504040 B/op	21007082 allocs/op

~ benchcmp old.txt new.txt
benchmark                           old ns/op       new ns/op       delta
BenchmarkReaderBasic-12             407533          312549          -23.31%
BenchmarkReaderReplace-12           429914          318810          -25.84%
BenchmarkReaderReplaceTwo-12        435556          330967          -24.01%
BenchmarkAggregateCount_100K-12     6798974         4149588         -38.97%
BenchmarkAggregateCount_1M-12       65657411        37746503        -42.51%
BenchmarkSelectAll_10M-12           20882119900     17608495800     -15.68%

benchmark                           old allocs     new allocs     delta
BenchmarkReaderBasic-12             957            338            -64.68%
BenchmarkReaderReplace-12           957            340            -64.47%
BenchmarkReaderReplaceTwo-12        957            341            -64.37%
BenchmarkAggregateCount_100K-12     308077         103261         -66.48%
BenchmarkAggregateCount_1M-12       3146610        1049435        -66.65%
BenchmarkSelectAll_10M-12           41978762       21007082       -49.96%

benchmark                           old bytes      new bytes      delta
BenchmarkReaderBasic-12             397860         101920         -74.38%
BenchmarkReaderReplace-12           397844         101993         -74.36%
BenchmarkReaderReplaceTwo-12        397855         102012         -74.36%
BenchmarkAggregateCount_100K-12     16667102       3553623        -78.68%
BenchmarkAggregateCount_1M-12       168057743      33827931       -79.87%
BenchmarkSelectAll_10M-12           2758799896     1416504040     -48.66%
```

```
BenchmarkReaderHuge/97K-12         	    2200	    540840 ns/op	 184.32 MB/s	 1604450 B/op	     687 allocs/op
BenchmarkReaderHuge/194K-12        	    1522	    752257 ns/op	 265.04 MB/s	 2143135 B/op	    1335 allocs/op
BenchmarkReaderHuge/389K-12        	    1190	    947858 ns/op	 420.69 MB/s	 3221831 B/op	    2630 allocs/op
BenchmarkReaderHuge/778K-12        	     806	   1472486 ns/op	 541.61 MB/s	 5201856 B/op	    5187 allocs/op
BenchmarkReaderHuge/1557K-12       	     426	   2575269 ns/op	 619.36 MB/s	 9101330 B/op	   10233 allocs/op
BenchmarkReaderHuge/3115K-12       	     286	   4034656 ns/op	 790.66 MB/s	12397968 B/op	   16099 allocs/op
BenchmarkReaderHuge/6230K-12       	     172	   6830563 ns/op	 934.05 MB/s	16008416 B/op	   26844 allocs/op
BenchmarkReaderHuge/12461K-12      	     100	  11409467 ns/op	1118.39 MB/s	22655163 B/op	   48107 allocs/op
BenchmarkReaderHuge/24922K-12      	      66	  19780395 ns/op	1290.19 MB/s	35158559 B/op	   90216 allocs/op
BenchmarkReaderHuge/49844K-12      	      34	  37282559 ns/op	1369.03 MB/s	60528624 B/op	  174497 allocs/op
```

docs/select/README.md

@@ -106,3 +106,4 @@ For a more detailed SELECT SQL reference, please see [here](https://docs.aws.ama
 - Large numbers (outside of the signed 64-bit range) are not yet supported.
 - The Date [functions](https://docs.aws.amazon.com/AmazonS3/latest/dev/s3-glacier-select-sql-reference-date.html) `DATE_ADD`, `DATE_DIFF`, `EXTRACT` and `UTCNOW` along with type conversion using `CAST` to the `TIMESTAMP` data type are currently supported.
 - AWS S3's [reserved keywords](https://docs.aws.amazon.com/AmazonS3/latest/dev/s3-glacier-select-sql-reference-keyword-list.html) list is not yet respected.
+- CSV input fields (even quoted) cannot contain newlines even if `RecordDelimiter` is something else.

go.mod

@@ -29,6 +29,7 @@ require (
 	github.com/hashicorp/vault v1.1.0
 	github.com/inconshreveable/go-update v0.0.0-20160112193335-8152e7eb6ccf
 	github.com/json-iterator/go v1.1.7
+	github.com/klauspost/compress v1.5.0
 	github.com/klauspost/pgzip v1.2.1
 	github.com/klauspost/readahead v1.3.0
 	github.com/klauspost/reedsolomon v1.9.1