interfaces: extend pulseaudio interface with slot side

[morphis]

This adds the slot side implementation to the pulseaudio interface.

The implementation itself is very rough at the moment but enables a pulseaudio snap build from https://code.launchpad.net/~morphis/snappy-hwe-snaps/+git/pulseaudio/+ref/add-initial-packaging being able to run, detect audio devices and record/play audio content.

I share this here for a initial discussion and review.

Open point:

• Add missing unit tests
• Identify desktop/core differentiation points
• Review and optimize security policy

[snappy-m-o]

Can one of the admins verify this patch?

[snappy-m-o]

Can one of the admins verify this patch?

[snappy-m-o]

Can one of the admins verify this patch?

[zyga]

whitelist this please

[zyga]

can you please merge master into this branch?

[snappy-m-o]

Can one of the admins verify this patch?

[snappy-m-o]

Can one of the admins verify this patch?

[snappy-m-o]

Can one of the admins verify this patch?

[come-maiz]

Hey @morphis, can we have a test for this like the one zyga added for cups? https://github.com/snapcore/snapd/blob/master/integration-tests/manual-tests.md#test-cups-interface-by-printing-something

[zyga]

ping @morphis (merge master into this, perhaps document a manual tests for this interface unless the pulseaudio snap is coming soon where we can postpone that for a while)

[morphis]

@zyga Will do that in a bit but priority for this was a bit dropped.

[zyga]

Ack, thanks for that @morphis

[morphis]

Closing as the new one is #1212

[snappy-m-o]

Can one of the admins verify this patch?

[snappy-m-o]

Can one of the admins verify this patch?

[snappy-m-o]

Can one of the admins verify this patch?