Modularize federation (Option 2)

[poojanilangekar]

Based on the discussion in the community sync, this PR modularizes federation calls to a separate factory. The specific instances of the NonRESTCatalogFactory is loaded only when a non-REST catalog is initialized and accessed. Beyond the catalog initialization, all the calls are identical for internal and federated catalogs.

Based on the discussion in #2301, this PR removes the compile-time flag used to build the HadoopFederatedCatalogFactory.

Testing:
Applied the regtest in PR #2286.

[poojanilangekar]

CC: @eric-maynard @dennishuo @adutra

[eric-maynard]

If @snazy is okay with using this approach for HMS federation, then I think it's preferable to option 1

[snazy]

Yea, thanks for removing the conditional build parameter. One comment though. But otherwise I'm fine with it.

[snazy]

THose are superfluous, as those are the enum names, and can therefore be removed.

[poojanilangekar]

We still need these because we can't use ConnnectionType.ICEBERG_REST.name() or ConnectionType.HADOOP.name(). The annotations needs to be constant expressions. Here's the error for your reference.

The value for annotation attribute Identifier.value must be a constant expressionJava(536871525)

[adutra]

You may want to just return name().toLowerCase(Locale.ROOT) – since most CDI identifiers in Polaris (if not all) are lower-case.

Suggested change

	public String getFactoryIdentifier() {
	switch (this) {
	case ICEBERG_REST:
	return ICEBERG_REST_FACTORY_IDENTIFIER;
	case HADOOP:
	return HADOOP_FACTORY_IDENTIFIER;
	default:
	throw new UnsupportedOperationException(
	"No factory identifier for connection type: " + this);
	}
	}
	public String getFactoryIdentifier() {
	return name().toLowerCase(Locale.ROOT);
	}

[poojanilangekar]

We can't use the name().toLowerCase() directly because of two reasons:

1. We need the annotations to be constants. (Please see my comment above)
2. We need to explicitly handle the NULL_TYPE/default case.

To make things consistent, I've changed the declarations to use lower case.

[dennishuo]

LGTM

[dennishuo]

Looks like other comments have also been addressed, merging now.