jack: implement some missing methods

to make qjackctl 0.9.0 work
4 jobs for master in 1 minute and 37 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Container
passed container_fedora #7101028

00:00:30

 
  Build
passed build_on_fedora #7101029

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  Pages
passed pages #7101030

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  Deploy
passed pages:deploy

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