Make Stellar wallet an optional (opt-in) module

Stellar is an insecure (useless?) (pyramid scheme?) (pump and dump scheme by venture capitalists?) fork of the Ripple Protocol (scam!) - see more here: https://twitter.com/francispouliot_/status/1042180860580122625

**NOT A RISK, SEE COMMENTS BELOW**: Having a stellar lumens wallet exposes users to legal liabilities, including, in Canada, an obligation to divulge that they are cryptocurrency owners. The requirement in Canada states that users must divulge all cryptocurrency addresses under their control.

The economics of Lumens are built so that the value of the coin will tend towards zero, with no incentive for holders. Because it is NOT a trustless decentralized consensus algorithm, rather a consortium of legally-liable trusted nodes, it is not a reliable payment method and as such has not seen widespread merchant adoption. The fact that startups are literally giving away millions of dollars worth of lumens should be extremely alarming.

**NOT A RISK, SEE COMMENTS**: As such, it is very detrimental to Keybase users to be forced to expose themselves to legal liability of having a lumens wallet, with little to no upside.

**STILL VALID**: In addition, it can only be described as a pyramid scheme, and is fundamentally insecure.

To protect the Keybase user experience and to protect the privacy of users, I strongly urge Keybase to make the Lumens wallet an optional, opt-in feature. A simple "I want a Stellar Wallet" option when downloading the client would be great.

Thanks for understanding,

One of your biggest users and fans.

[edits in bold]

The issue names no files, tests, or entry points. Start by locating the Stellar wallet and client installation flow, then read the 14-comment thread for an agreed scope. Done would require a maintainer-approved opt-in design and implementation, with the resulting behavior verified by relevant tests.

Written by the indexing model from the issue text.