Add Engineering Lead position to Careers page

[krivard]

Eng Lead position is posted!: Software Engineering Manager

We should add this to the Careers page asap.

Here's the directory with all the job blurbs, the easiest way is to make a copy of an existing one and then change the metadata to fit.

[dshemetov]

We added this last week here, but there are still some grammatical oddities (courtesy of your truly) in the blurb that we should probably fix