Correct types, permissions, etc. of logos of support companies.

[mike-jumper]

It was unfortunately not readily apparent that the PNG logo for "Bitchief Technology Services" provided via #142 was not actually a PNG image, but rather a JPEG that was erroneously given a .png extension.

These changes corrects this by saving the original logo as an actual PNG. Additionally, these changes:

• Correct the UNIX filesystem permissions of the "Dove IO" logo (definitely does not need the execute bit set).

• Run all logos through pngcrush to shrink their size as much as possible (this only affected the "Arcisphere", "Bitchief Technology Services", and "Dove IO" logos):

  [mjumper@mdesktop companies]$ git show --stat HEAD
  commit 9fdb93c4f4b7b2174c20152f92d8310c743cd4d4 (HEAD -> fix-company-images, origin/fix-company-images)
  Author: Michael Jumper <[email protected]>
  Date:   Tue Apr 9 13:10:32 2024 -0700
  
      Run all support provider logos through pngcrush.
  
   images/companies/arcisphere-llc.png | Bin 7667 -> 7317 bytes
   images/companies/bitchief.png       | Bin 15001 -> 13547 bytes
   images/companies/doveio-llc.png     | Bin 9123 -> 5694 bytes
   3 files changed, 0 insertions(+), 0 deletions(-)
  [mjumper@mdesktop companies]$