Update reference to OpenJ9 to be Eclipse OpenJ9

Change "OpenJ9" to "Eclipse OpenJ9" in all necessary places

The name of the images that reference OpenJ9 can used "openj9"
Title and descriptions of the images needs to use "Eclipse OpenJ9" for the first occurrence
and then "OpenJ9" for the subsequent occurrences.

(according to https://www.eclipse.org/legal/logo_guidelines.php#Proper_Usage_of_Eclipse_Trademarks, section 1)