Migrate from stumbleupon to mix

[sshcli]

StumbleUpon moved to Mix
All StumbleUpon references must be replaced by mix.

Example error in Kunena:

[Ruud68]

What are the new urls? Both for sharing and share counter? Looked into this some time ago but could not find any information.

[sshcli]

@Ruud68 I don't know.
Maybe @tabalinas knows

[Ruud68]

There is no documentation yet (I didn't find any) I just switched of stumblepon in config so it doesn't show in Kunena any more pending the mix urls

[Ruud68]

Just as a quick reference: https://community.mix.com/blog/2018/7/12/add-a-mix-badge

[Ruud68]

Hi, just created a PR #210 to replace StumbleUpon with Mix. added the FA5 icon as there is no FA4 icon.
This PR also adds the missing js code for Reddit (only css got merged?) #184
@tabalinas, can you also have a look at the other PR's and when fit, commit them? It is getting difficult to maintain a consistent and working version :S