Merge branch '1971-double-precision-parameters' into 'develop'

Added 'double' application parameter type.

Closes #1971

See merge request !628
2 jobs for nightly in 9 minutes and 56 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Precheck
passed #16792
fast-build

00:09:56

 
  External
passed cdash:ubuntu-18.04-fast