bt5_prototype: Add export functions for PathTempalteItem and BusinessPackage as well as make createInstallationData more efficient

As now, we expect our catalog object to be erp5 catalog and not indexable,
so its important to not reindex or unindex the old object.

Earlier, In ERP5Site, we use property 'isIndexable' to have control over indexing and unindexing.
This was usefull specially in case of bootstrap. To have this control, we had a function
`isIndexable` in SQLCatalog which we used to switch for enabling-disabling indexation. (769f9fb2)

Now, we do have ERP5 Catalog, which itself is an ERP5 Object, hence it has an accessor `isIndexable`
of itself which we plan to disable for now(as we don't want circular dependency while indexing
catalog in itself). But as we did have a function `isIndexable` in SQLCatalog which had control
over the indexing, we needed to rename this property for ERP5Site.

Hence, now we use property 'isIndexingRequired' for ERP5Site and use to have overall control
over indexing process.

Please note, we do not intend to change the same property name for any other object. Its just
for ERP5Site.

Required as most of the changes we have are in erp5_core and that's
why its important to install/update it before we install erp5_catalog_storage
bt5.

For compatibilty, we have added 2 extra functions, but in no way we need
to use this attribute as it doesn't give any meaning for ERP5CatalogTool
to have a default SQL Catalog.

This would increase compatibility between accessors in erp5_catalog and
remove the need of copy and patch. At the same time, it also helps in
increasing performance as using _getOb is always less costly than
getattr, as it reduces the need to look in acquisition.

After adding document component object, _p_oid was bing generated at the
last step of commit hook. This led to problem that _registry_dict for
dynamic_class 'erp5.component.document' wasn't getting updated with
the _p_oid of the component created. This led to failing of test because
to validate object with same reference, the checkConsistency function
checks in the _registry_dict for reference and _p_oid.

Explicilty calling commit here generates the oid before validation, hence
make it available for the registry_dict in time.

But, this clearly is a workaround which is clearly not solving the real
problem of why the _p_oid isn't being generated at the right step.

Also, me(Ayush), tried to recreate this error on a running instance, but
it worked fine there.