Add more information about configuring and troubleshooting TLS to the Beats docs

[dedemorton]

Andrew wrote this awesome document about configuring TLS: https://gist.github.com/andrewkroh/fdc7e5f3f0f0ed63a11c

We need create a topic based on this document and add it to the sections about configuring each beat.

[monicasarbu]

@dedemorton This should be an easy one to include in our docs, right? We get more questions on discuss regarding this.