Rename `MongoItemReader` to `MongoPagingItemReader`

[fmbenhassine]

With #4323 planned for 5.1, the MongoItemReader should be renamed to MongoPagingItemReader as it uses paging to read data from MongoDB. This naming change is for consistency with other reader implementations like JDBC (JdbcCursorItemReader / JdbcPagingItemReader), JPA (JpaCursorItemReader, JpaPagingItemReader), etc.

[sukanth]

@fmbenhassine i can do this too :-)

[fmbenhassine]

@sukanth Thank you for all your effort and PRs! I like the momentum you got on the project 👍

However, this one is tagged with status: for-internal-team, which means we prefer keeping it for the internal team to work on.

Thank you for your offer to help anyway.

[sukanth]

@sukanth Thank you for all your effort and PRs! I like the momentum you got on the project 👍

However, this one is tagged with status: for-internal-team, which means we prefer keeping it for the internal team to work on.

Thank you for your offer to help anyway.

No Problem Thank you :-)