Make default pack extensions configurable and default to png and gif

7 jobs for feature/configurable-pack-extensions in 8 minutes and 52 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #40502
build

00:02:57

 
  Test
passed #40506
analysis

00:03:12

passed #40505
lint

00:00:55

passed #40503
unit-testing

00:04:07

81.0%
passed #40504
unit-testing-rum

00:05:54

 
  Deploy
manual #40507
allowed to fail manual
review_app
manual #40508
allowed to fail manual
stop_review_app