No user oriented network configuration in `microcloud init` or in a documentation

[nobuto-m]

$ snap list microcloud lxd
Name        Version         Rev    Tracking     Publisher   Notes
lxd         5.21.3-c5ae129  33110  5.21/stable  canonical✓  in-cohort
microcloud  2.1.1-202e275   1781   2/stable     canonical✓  in-cohort

We have the following step in microcloud init of asking what network interface should be used for MicroCloud's internal traffic.

$ sudo microcloud init
Waiting for services to start ...
Do you want to set up more than one cluster member? (yes/no) [default=yes]: 
Select an address for MicroCloud's internal traffic:          
 Filter | <type to filter rows>
   ┌─────────────────┬─────────┐
   │     ADDRESS     │  IFACE  │
   ├─────────────────┼─────────┤
 ✓ │ 192.168.123.232 │ enp1s0  │
   │ 192.168.101.205 │ enp8s0  │
   │ 192.168.102.171 │ enp9s0  │
   │ 192.168.103.186 │ enp10s0 │
   └─────────────────┴─────────┘
 space to select; enter to confirm
 ↑/↓ to move; → to select all; ← to select none

However, there is no question about how to expose MicroCloud for users. In reality, it looks like the internal network is assumed for users to use to reach out to LXD API, MicroCloud dashboard (LXD UI) etc. That's confusing from a UX point of view. We should ask where they want to expose Microcloud on, and where to use for real internal traffic. Of course those traffic separation is optional.

There is no mention to users (web browser, LXD API client, etc.) in networking documents:

• https://documentation.ubuntu.com/microcloud/latest/microcloud/explanation/networking/
• https://documentation.ubuntu.com/microcloud/latest/microcloud/reference/requirements/

[roosterfish]

Let's add a line to the docs mentioning that what is selected for internal traffic will also be consumed by end users to reach out to LXD.