Create and use a ConnectionStatus enum

[dilyn-corner]

Description

This PR attempts to satisfy the requirements of #42 by introducing a new ConnectionStatus enum type.

The variants of ConnectionStatus are intended to align with the official Nina documentation, but slightly renamed to be more informative.

The enum is currently defined in src/wifi.rs as a forward-looking design move.

GitHub Issue: Closes #42

Changes

• Replace direct byte comparison with ConnectionStatus enum

Testing Strategy

Testing cross/ in the usual way should work as intended. There should be no functional difference in this PR. (I have not run tests).

Concerns

I worked with Jim on this as an intro problem, the changes in src/{lib.rs,spi.rs} are my own guesses :)

At least two variants should be explored further, and they have comments explaining why.

[dilyn-corner]

Officially ran tests which revealed some obvious oversights. I think I did the use ... correctly.

Only one thing missing, in get_conn_status. Is marked as // TODO:.

Warnings were almost all resolved in a different branch, I think? The legitimate complaints here are the lacking docs on the variants for ConnectionStatus.

[github-advanced-security]

clippy found more than 10 potential problems in the proposed changes. Check the Files changed tab for more details.

[dilyn-corner]

Should be good to go now!

Added some extra stuff to wifi.rs because it seemed sane to go in there.

Todos left:

• document variants
• rebase

[dilyn-corner]

I would like to draw attention to a3176b0

I removed this comments after a bit of digging.

It looks like WL_IDLE_STATUS is a purely "internal" return value if I'm reading the code correctly. WL_IDLE_STATUS is returned periodically, for instance see WiFiClass::begin(const char* ssid) (and throughout). It seems like this is expected to be returned by us, and not by the Esp32.

As for ApFailed, it looks like it is used in exactly two locations, both here. So it isn't unused as previously commented.

[jhodapp]

Looking good, one inline question to think about.

[calebbourg]

This looks great!

I left one thought as well.

[jhodapp]

Looks very good! Well done and thank you Dilyn!