feat: allow includeCollections option in constructor

[10kc-tenzin-mahabir]

Added includeCollections option in constructor to be able to specify which collections of the database will be included in the snapshots

• This allows users to avoid taking snapshots of unneeded collections

[lihaibh]

Thank you for the contribution. You can already do it, using 'collections' property. take a look here: https://github.com/lihaibh/ditto/blob/master/src/connectors/Connector.ts

you can filter collections either on your target connector or on your source connector, or both.