make a transaction pool page and home page reference for web explorer

[GlenDC]

Currently the web explorer does not officially support checking out the transaction pool. It is however pretty useful, and you can already check it by directly going to the endpoint as defined by Rivine.

It would be cool if:

• the home page has a transaction pool button, to view all transactions currently in the pool waiting (even more cool if it already specifies directly as some sub text how many transactions are currently waiting in the queue);
• there is a /pool page that lists all transactions currently in the transaction pool.