Use Mozilla's corporate Akismet account

[hoosteeno]

As seen on Bugzilla[0]...

In bug 1194731 the MDN team worked with the legal team to establish an enterprise account with Akismet. This account entitles us to enterprise service and includes some additional safeguards for users whose information might be sent to Akismet for spam checking. We should use that account instead of any other.

Account information is here: https://intranet.mozilla.org/Engagement/MDN#Tools

[0] https://bugzilla.mozilla.org/show_bug.cgi?id=1232425