As part of the LiteParsedPipeline expansion for desugar stages, we must implement new specializations of LiteParsedDocumentSource:
https://docs.google.com/document/d/1mEAk6lF4zMJbIFTxVaBKWsq2JLcKwOBQdzClqaLtO8U/edit?tab=t.cmh028a5t5iy#bookmark=kix.odhqha3zsmvr 

As part of this ticket, implement DocumentSourceExtension::LiteParsed & DocumentSourceExtension::LiteParsedExpanded.

At instantiation time, DocumentSourceExtension::LiteParsed should recursively generate its expanded pipeline and keep it as a private/protected member. 

At expansion time:
1. If the extension returns a host: : ParseNode, parse it into a LiteParsedDocumentSource.

2. If the extension returns an extension ParseNode, instantiate a DocumentSourceExtension::LiteParsed and continue recursively expanding

3. If the extension returns an extension AstNode, instantiate a DocumentSourceExtension::LiteParseExpanded. 

For this ticket, do not implement depth validation, it will be tackled instead in SERVER-109558