Add metadata extractor for dremio

[ravisuhag]

Deliverables

• add unit tests
• add extractor
• add README.md in plugins/extractors/mysql, defining output
• register your extractor plugins/extractors/populate.go
• add extractor the extractor list in docs/reference/extractor.md

Output must contain a Table

Table

Field	Sample Value
urn	my_database.my_table
name	my_table
source	dremio
description	table description
profile.total_rows	2100
schema	[][Column]

Column

Field	Sample Value
name	total_price
description	item's total price
data_type	decimal
is_nullable	true
length	12,2