[feature/change] Pre-generate ZeroTier Identity Keys in Advance Using OpenWISP

[Aryamanz29]

To support #606, it is necessary to pre-generate the ZeroTier identity.secret and identity.public files in advance using OpenWISP, as mentioned in the following discussion thread:

discuss.zerotier.com/t/can-i-create-a-custom-node-id-in-openwrt/3082.

The purpose of this task is to ensure that the necessary identity keys are generated beforehand, enabling the desired custom node ID functionality in OpenWRT.

Possible Steps:

• Using zerotier-idtool to generate ZeroTier identities.

zerotier-idtool generate identity.secret identity.public

• Configure the device's configuration variables and file configuration to manage ZeroTier identities when adding the ZeroTier VPN client template to the device. Please note that the mentioned steps can be automated once we have discussed them.

Dependencies

• [change] Make the host field of the VPN model configurable for ZeroTier Controllers #769
• [feature] Manage ZeroTier networks using the ZeroTierServiceAPI #768

[pandafy]

Completed in #778