Adds Jeremy Prevost speaker info

Also re-adds Matt Bernhardt which was lost in a recent commit.

Author: JPrevost

_data/speakers.yml

@@ -337,10 +337,14 @@
   name: Jeremy Prevost
   last: Prevost
   pronouns: he/him
-  institution:
-  position-title:
-  bio:
-  image_alt:
+  institution: MIT Libraries
+  position-title: Lead Engineer
+  bio: "When not working on some of the coolest acronymed library discovery products
+    ('TIMDEX Is Making Discovery EXcellent' and 'TACOS: Totally Awesome Categorization Of Searchterms'), Jeremy can often
+    be found decorating frisbees in his basement and then throwing them at trees with family and friends."
+  image_src: /assets/img/speakers/jeremy-prevost.jpg
+  image_alt: "Jeremy, a middle aged white man with short hair, black glasses, and a grey and brown beard is wearing a 
+    tan sweater. In the background are two blurred computer screens with text that is very likely code."
   keynote: false
 - id: jeremy-thompson
   name: Jeremy Thompson
@@ -475,11 +479,12 @@
 - id: matt-bernhardt
   name: Matt Bernhardt
   last: Bernhardt
-  pronouns: he/him
-  institution:
-  position-title:
-  bio:
-  image_alt:
+  institution: MIT Libraries
+  position-title: Senior Software Engineer
+  bio: "Matt (he /him) is a senior software engineer at the MIT Libraries on discovery and CMS projects. He has previously worked as an educational technology professional across a variety of contexts: web development and design, digital fabrication, data visualization and modeling, and technology support. He holds an architecture degree from Ohio State University. Outside of work, he pays too much attention to space, soccer, and F1."
+  image_src: "/assets/img/speakers/matt-bernhardt.jpg"
+  image_alt: "Matt is a balding middle-aged white male, with wire rim glasses, wearing a collared button down shirt. He has a laptop bag over his shoulder, and he is squinting slightly into bright daylight."
+  slack: matt-bernhardt
   keynote: false
 - id: matthew-elliott
   name: Matthew Elliott