feat!: list_databases returns an iterator (#4442)

CatalogConnection.list_databases should return an iterator so that users
don't have to manually re-implement pagination. For those who do want
more control over pagination, add num_page_results and page_token to the
Iterator object, and also allow the iterator object to be created at a
specific page token.

docs/src/js/classes/DatabaseNames.md

@@ -0,0 +1,79 @@
+[**@lancedb/lancedb**](../README.md) • **Docs**
+
+***
+
+[@lancedb/lancedb](../globals.md) / DatabaseNames
+
+# Class: DatabaseNames
+
+A lazy async iterator of database names with pagination state.
+Returned by [Catalog.listDatabases](Catalog.md#listdatabases).
+
+## Implements
+
+- `AsyncIterableIterator`<`string`>
+
+## Methods
+
+### \[asyncIterator\]()
+
+```ts
+asyncIterator: AsyncIterableIterator<string>
+```
+
+#### Returns
+
+`AsyncIterableIterator`&lt;`string`&gt;
+
+#### Implementation of
+
+`AsyncIterableIterator.[asyncIterator]`
+
+***
+
+### next()
+
+```ts
+next(): Promise<IteratorResult<string, any>>
+```
+
+Fetch the next name, requesting another page only when needed.
+
+#### Returns
+
+`Promise`&lt;`IteratorResult`&lt;`string`, `any`&gt;&gt;
+
+#### Implementation of
+
+`AsyncIterableIterator.next`
+
+***
+
+### numPageResults()
+
+```ts
+numPageResults(): number
+```
+
+Number of names available without another REST request.
+
+#### Returns
+
+`number`
+
+***
+
+### pageToken()
+
+```ts
+pageToken(): undefined | string
+```
+
+Token for the next REST request. Initially this is the supplied starting token.
+Returns undefined after the final page is fetched, even if names remain cached.
+Drain the cache before saving a token to avoid skipping names when resuming.
+A failed request terminates iteration and retains its token for a new iterator.
+
+#### Returns
+
+`undefined` \| `string`