Migrate Java Code from Spring Data MongoDB to MongoDB Driver Reactive Streams: A Step-by-Step Guide

The migration of Example 1 and Example 2 is from spring-data-mongodb to mongodb-driver-reactivestreams, which involves changes in the syntax and usage of the API. The most significant changes are:

1. The use of 'Flux' instead of 'MongoTemplate' to create and execute aggregations.
2. The use of 'dbClient.getCollection()' instead of 'mongoTemplate.aggregate()' to access collections.
3. The use of 'Filters', 'Aggregates', 'Accumulators', 'Projections' and other classes from the 'com.mongodb.reactivestreams.client' package instead of the corresponding classes from 'org.springframework.data.mongodb.core.aggregation'.
4. The use of 'Document.parse()' to convert strings into documents.

The 'Translate' snippet is already in the format of mongodb-driver-reactivestreams and does not require any further migration.