[SPARK-14070][SQL] Use ORC data source for SQL queries on ORC tables

## What changes were proposed in this pull request?

This patch enables use of OrcRelation for SQL queries which read data from Hive tables. Changes in this patch:

- Added a new rule `OrcConversions` which would alter the plan to use `OrcRelation`. In this diff, the conversion is done only for reads.
- Added a new config `spark.sql.hive.convertMetastoreOrc` to control the conversion

BEFORE

```
scala>  hqlContext.sql("SELECT * FROM orc_table").explain(true)
== Parsed Logical Plan ==
'Project [unresolvedalias(*, None)]
+- 'UnresolvedRelation `orc_table`, None

== Analyzed Logical Plan ==
key: string, value: string
Project [key#171,value#172]
+- MetastoreRelation default, orc_table, None

== Optimized Logical Plan ==
MetastoreRelation default, orc_table, None

== Physical Plan ==
HiveTableScan [key#171,value#172], MetastoreRelation default, orc_table, None
```

AFTER

```
scala> hqlContext.sql("SELECT * FROM orc_table").explain(true)
== Parsed Logical Plan ==
'Project [unresolvedalias(*, None)]
+- 'UnresolvedRelation `orc_table`, None

== Analyzed Logical Plan ==
key: string, value: string
Project [key#76,value#77]
+- SubqueryAlias orc_table
   +- Relation[key#76,value#77] ORC part: struct<>, data: struct<key:string,value:string>

== Optimized Logical Plan ==
Relation[key#76,value#77] ORC part: struct<>, data: struct<key:string,value:string>

== Physical Plan ==
WholeStageCodegen
:  +- Scan ORC part: struct<>, data: struct<key:string,value:string>[key#76,value#77] InputPaths: file:/user/hive/warehouse/orc_table
```

## How was this patch tested?

- Added a new unit test. Ran existing unit tests
- Ran with production like data

## Performance gains

Ran on a production table in Facebook (note that the data was in DWRF file format which is similar to ORC)

Best case : when there was no matching rows for the predicate in the query (everything is filtered out)

```
                      CPU time          Wall time     Total wall time across all tasks
================================================================
Without the change   541_515 sec    25.0 mins    165.8 hours
With change              407 sec       1.5 mins     15 mins
```

Average case: A subset of rows in the data match the query predicate

```
                        CPU time        Wall time     Total wall time across all tasks
================================================================
Without the change   624_630 sec     31.0 mins    199.0 h
With change           14_769 sec      5.3 mins      7.7 h
```

Author: Tejas Patil <tejasp@fb.com>

Closes #11891 from tejasapatil/orc_ppd.