Codespel run with the same arguments as described in
commit 58510ed56679 ('docs: misc. typos pt2').

(cherry picked from commit bf0c4e6ac2855088e3962693886bb6ab71856f7b)

(cherry picked from commit 3990c92fbf4789d8de2264b39f9d1b690f5dd4d5)

A NetworkManager client requires an API to validate and decode
a base64 secret -- like it is used by WireGuard. If we don't have
this as part of the API, it's inconvenient. Expose it.

Rename it from _nm_utils_wireguard_decode_key(), to give it a more
general name.

Also, rename _nm_utils_wireguard_normalize_key() to
nm_utils_base64secret_normalize(). But this one we keep as internal
API. The user will care more about validating and decoding the base64
key. To convert the key back to base64, we don't need a public API in
libnm.

This is another ABI change since 1.16-rc1.

(cherry picked from commit e46ba0186720bfe5e31dcad9a5001a415deb9ce6)

(cherry picked from commit 626beaf83e142fcaff32dbf1662d75af1d826b2d)

This adds new API for 1.16.0 and is an ABI break since 1.16-rc1.

(cherry picked from commit d5e93ae613fd355351bdf37530cae3d3dfb4e5ba)

That is slightly complex, because we need to (DNS) resolve the endpoints,
and we also have to retry periodically. For example, initially we may be
unable to resolve an endpoint, but later we may be.

What is also interesting is that during assume and reapply, we may not
have all information in the profile. Most notably, the private keys will
be missing. We need to cope with that and not reconfigure keys. However,
we still need to resolve names and update the endpoints.

Configuring peers (and allowed-ips of the peers) is not
yet supported.

For now only add the core settings, no peers' data.

To support peers and the allowed-ips of the peers is more complicated
and will be done later. It's more complicated because these are nested
lists (allowed-ips) inside a list (peers). That is quite unusual and to
conveniently support that in D-Bus API, in keyfile format, in libnm,
and nmcli, is a effort.
Also, it's further complicated by the fact that each peer has a secret (the
preshared-key). Thus we probably need secret flags for each peer, which
is a novelty as well (until now we require a fixed set of secrets per
profile that is well known).

For now, the device only exposes partial link status (not including
peers). It cannot create new links.