Changes:
- Updated the old (now invalid) osquery slack invitation link to go to
fleetdm.com/slack (which redirects to a valid osquery slack invitation)
* Articles housekeeping
Style tweaks:
- reduced categories-and-search margin-top
- changed color of category on cards
- removed time stamps from cards
Image updates:
- created missing images, and replaced existing with a cleaner, more vibrant style to the following categories.
- security
- guides
- engineering
- podcasts
- Normalized release thumbnails. The current graphics are over-designed, inconsistent, and too busy/hard to process.
* lint fix
* remove ")" from image caption
* remove old article images
* update cover image filenames for consistency
* add deleted image, update filenames to match naming conventions
* fix typo in filename
Co-authored-by: Eric <eashaw@sailsjs.com>
