Get out of devmode

[happyaron]

We need to get the snap out of devmode so it can publish into the Snap Store.

There are two modes that can be accepted into the Snap Store:

• strict: preferred, all constraints are there, can submit directly
• classic: loosely confined, but need approval from Snap Store team - snapcraft itself is using this mode in the mean time

Known issues:

1. Users will have to manually connect some privileged interfaces to our snap, this is by design of snap which requires user's participation when these privileges need to be granted.
2. Some privileges are never exposed by the Snap Core, so that some of the implementation details would need to be changed