feat: New paths for API

[aadarsh-ram]

What

• Adds GET paths for finding entry parents and children
• Adds POST path for updating entry children
• Adds POST paths for creation of new root node
• Adds DELETE path for deleting a node
• Some helper functions have also been created

Related issue(s)

• Fixes Paths for updating relationships of a node #38
• Fixes Paths for adding/delete nodes #75

[alexgarel]

@aadarsh-ram kudos for your code which is correct and well organized.

I commented on some improvement that I see necessary (some are more on style).

I think we should really avoid short names like a, b etc. in our queries and use descriptive name, this really helps understand the code in a fluid way. (coming from outside, I see this more clearly as I review the code).

[alexgarel]

Some suggestions to apply ! And there we are.

[alexgarel]

Thanks for the good work.