Converts site to a blogging site with first Knowledge Commons post

[Frijol]

In addition to adding the Knowledge Commons blog post, removes "Public Record" from the menu (without deleting the file), removes the homepage from the menu, and renames "Menu" to "Blog".

[Frijol]

Ready for review! Looks like:

Authorship: Please PR or comment as much if you want to be added as an author! @ericnost @meiqimichelle @lightandluck in particular (the Google Doc says you edited)

Next steps:

• I'll leave this open for a week (until EOD 6/5) to make sure any last edits or authorship get added
• We need a +1 from a representative from EDGI, QRI, and Protocol Labs as this is a quotidian but nontrivial change

Other: Both technical and nontechnical (e.g. titling, line edits in the blog post) are welcome. On the technical end, I went as simple as possible; we can add features later.