[Feature][API][backend] Query all upstream and downstream dependencies of the task

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Describe the feature In order to view the dependency realations of one task node clearly,It’s necessary to query the upstream and downstream dependencies of this task.

1.According to the process definition id and task name, you can get its direct upstream and downstream dependencies. 2.Only need to get the direct dependencies here, instead of recursively querying all the dependencies. 3.Query the dependencies can support three query types.

• Upstream dependency
• Downstream dependency
• Upstream and downstream dependency.

Design detail

There is process_definiton_json field in the process definition table. The tasks field is a task array that records all tasks. This json needs to be parsed to get the upstream and downstream dependencies of tasks.

The json structure of tasks For the json structure of tasks, you can see the picture below.

[IamMujuziMoses]

Thank you @lgcareer @djkevincr, I am looking forward to working on this and accomplishing with your help

[lgcareer]

@iamMujuziMoses Congratulations to you and welcome you selected this feature,if you have any question,you can feel free to ask and discuss here.