Add more useful links in resources.md in DP

[dubesar]

Add some more useful links in resources for Dynamic programming. Maybe it is a tutorial to DP or some useful tricks.

[thiago-h]

I will contribute to it

[Keenal]

I can work on this, if it's still needed!

[dubesar]

@Keenal this section can grow as much as possible , any input for this will be much more appreciated.

[Kadivendi]

I have some more suggestions for good resources. Can I pick this?

[NirmalSilwal]

I would like to contribute. I can share some interesting resources for DP. Can I make a PR on it?

[cdhiraj40]

@dubesar what's remaining in this issue? if there is still something to contribute then I would like to work on this :)