Implements Mempool endpoint

[thepabloaguilar]

Fixes #71

Motivation

Implementing Mempool endpoint.

Solution

To get the transactions in "memory" I've used the txpool_content method which returns all pending and queued transactions. More about on https://geth.ethereum.org/docs/rpc/ns-txpool#txpool_content

[thepabloaguilar]

@shrimalmadhur could you review this PR if possible, please?

[thepabloaguilar]

@shrimalmadhur do I need to do something more to merge? Btw, I don't have access to the merge button

[shrimalmadhur]

@shrimalmadhur do I need to do something more to merge? Btw, I don't have access to the merge button

@thepabloaguilar there is problem on our side. I am trying to fix it. You don't have to do anything. will circle back once I fix it.

[thepabloaguilar]

Ok, thanks a lot @shrimalmadhur

[shrimalmadhur]

@thepabloaguilar merged it now. apologies for the delay. we had some internal issues with approval.

[thepabloaguilar]

No worries @shrimalmadhur, thanks for the support! Btw, there's another approved PR of mine #87