Provide an example script for estimating the fee for a transaction and other diagnostic information
Provide an example script for estimating the fee for a transaction and other diagnostic information

Summary:
BitGo users commonly request a way to estimate the fee for a particular transaction prior to sending and without having to send the full amount. This example clearly depicts a manner in which a user can extract such information.

Example output:

```
Estimated Transaction Info

	Sending from:                        2Mts2jUYwLsRZVvMQiZH3z897w4Kz6isyDC
	Sending to:                          2NFj2zaLzt2enXoZ6x4jnq3wz98wHrWtu8G
	Amount:                              200000 satoshis

	Total number of inputs:              7
	Total number of outputs:             2
	Bitcoin network fee rate:            10000 (satoshis / kb)
	Estimated transaction size:          2133 bytes
	Estimated Bitcoin network fee:       21330 satoshis
	BitGo fee:                           0 satoshis

```

Reviewers: alex, benchan

Reviewed By: alex, benchan

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D3871

BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS