What's actually needed here is an explaination of how the license
applies along with the explanation where to find the full text.

Also, the libnm documentation was lacking the licensing information
altogether. Fix fixes it too.

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).

We named the types inconsistently:

  - "p2p-wireless" ("libnm-core/nm-setting-p2p-wireless.h")

  - "p2p" ("libnm/nm-p2p-peer.h")

  - "p2p-wifi" ("src/devices/wifi/nm-device-p2p-wifi.h")

It seems to me, "libnm/nm-p2p-peer.h" should be qualified with a "Wi-Fi"
specific name. It's not just peer-to-peer, it's Wi-Fi P2P.
Yes, there is an inconsistency now, because there is already
"libnm/nm-access-point.h".

It seems to me (from looking at the internet), that the name "Wi-Fi P2P"
is more common than "P2P Wi-Fi" -- although both are used. There is also
the name "Wi-Fi Direct". But it's not clear which name should be
preferred here, so stick to "Wi-Fi P2P".

In this first commit only rename the files. The following commit will
rename the content.

This adds the introspection data and P2P peer handling to libnm. To be
usable the P2P device handling is also needed.

The support is rather basic and only allows connecting to a specific
peer. However, this is actually already enough for many usecases.

Fixes: 7a59cd274485e4c0345c563d48e516967630d7f0

Remainder of typos found using `codespell -q 3 --skip="./shared,./src/systemd,*.po" -I ../NetworkManager-word-whitelist.txt` whereby whitelist consists of:
 ```
ans
busses
cace
cna
conexant
crasher
iff
liftime
creat
nd
sav
technik
uint
```

https://github.com/NetworkManager/NetworkManager/pull/205

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/2