Created Avro Schema to BigQuerySchema Convertor

[shashambhavi]

This PR introduces a new utility class, AvroToBigQuerySchemaTransform, to convert Avro schemas to BigQuery schemas. This is necessary for creating BigQuery tables dynamically based on the Avro schema of the incoming record in a Flink connector sink.

The following Type Conversions take place:
Reference: Type Conversions while loading avro file in BigQuery

Data Type Transformation:

Avro Type	BigQuery Type	Notes
string	STRING
bytes	BYTES
int	INT64
long	INT64
float	FLOAT64
double	FLOAT64
boolean	BOOL
enum	STRING
fixed	BYTES
record	RECORD
array	REPEATED
union(null, type)	NULLABLE type
logicalType: date	DATE
logicalType: time	TIME
logicalType: timestamp	TIMESTAMP
logicalType: local-timestamp	DATETIME
logicalType: decimal	NUMERIC/BIGNUMERIC	Depending on precision; STRING if precision is out of range
logicalType: geography_wkt	GEOGRAPHY
logicalType: uuid	STRING
logicalType: Json	JSON

Exception Handling:

Exception	Cause
IllegalArgumentException	The Avro Schema is not of RECORD type. Unsupported Avro Field of type UNION. Only ['datatype'], ['null', 'datatype'] or ['datatype', 'null'] are supported. Precision of decimal field must be non-negative. Scale of decimal field must be non-negative. Scale of the field cannot exceed precision. Array cannot have a NULLABLE element.
IllegalStateException	BigQuery ARRAY cannot have recursive ARRAY fields.
UnsupportedOperationException	BigQuery fields can only be nested 15 times. The Avro type of the field is not supported by BigQuery (e.g., MAP type). NULLABLE ARRAYS in UNION types are not supported.

/gcbrun