Add support for delete operations in MongoDB DAOs

[fmbenhassine]

As of v5.2.4, 6.0.0-RC1, the following methods are not implemented in MongoDB DAOs:

• org.springframework.batch.core.repository.dao.JobInstanceDao#deleteJobInstance
• org.springframework.batch.core.repository.dao.JobExecutionDao#deleteJobExecution
• org.springframework.batch.core.repository.dao.JobExecutionDao#deleteJobExecutionParameters
• org.springframework.batch.core.repository.dao.StepExecutionDao#deleteStepExecution
• org.springframework.batch.core.repository.dao.ExecutionContextDao#deleteExecutionContext(JobExecution)
• org.springframework.batch.core.repository.dao.ExecutionContextDao#deleteExecutionContext(StepExecution)