Enable a check on the transfer form to ensure users are not sending transfers to themselves

[netuoso]

Issue

Users are able to send a transfer to their own account through the wallet

Solution

When a user attempts to send a transfer to their own account, display a warning and disable the send button.

Summary

Right now, STEEM can be a very confusing places for users. Due to this, I believe it is a good idea to let the frontend provide as much assistance as possible while educating the user. If a user has multiple accounts, they will often need to send transfers between them. On condenser, a user has the ability to send a transfer to the account they are currently logged in as. While not very damaging, it is still confusing and might result in some users not getting their funds to where they were hoping.

Screenshots

[bnchdrff]

let's piggyback this one onto #1964

[netuoso]

@bnchdrff Done. Merged into #1964.

Closing this.