Schema name should be configurable

[gwenshap]

Is your feature request related to a problem? Please describe. Different companies have rules and standards about where they install extensions. As a result, most extensions support CREATE EXTENSION <name> SCHEMA <standard_schema>.

Unfortunately, AGE specifies the schema name in the control file, and as a result, it cannot be installed anywhere else: ERROR: extension "age" must be installed in schema "ag_catalog"

Describe the solution you'd like I'd like to see AGE support configurable installation schema via the standard Postgres syntax.