Add how-to for `lnd` self-signed TLS certificate management

By default, Chromium Browser / Google Chrome won’t recognize the self-signed TLS certificate prepared by lnd. This will prevent Joule from successfully connecting to lnd.

Chrome can be made to accept the self-signed cert by following these steps:

1. navigate to https://localhost:8080/v1/getinfo
2. click on the lock next to the URL and view the certificate
3. navigate to the certificate viewer’s “details” tab and export the cert to a file
4. navigate to edit > preferences > manage certificates > authorities > import
5. check all of the boxes and import the cert

Now Chrome should accept the cert and Joule should be able to connect to lnd!

[pseudozach]

I’ll also add how to import & trust the self-signed LND certificate on MacOS:

1. navigate to https://localhost:8080/v1/getinfo
2. click on the lock next to the URL and view the certificate
3. drag the certificate icon to a finder window to export the cert to a file
4. launch keychain access app and click “+” to import certificate
5. select the exported cert file to import it.
6. double-click the imported certificate, click trust and choose “Always trust” when using this certificate.

I hope it helps.

[openoms]

made a version to connect to a RaspiBlitz: https://github.com/openoms/bitcoin-tutorials/blob/master/JouleToRaspiBlitz.md