tapctl: refactor 'create' command

tapctl: refactor 'create' command

Make default adapter name selection logic more robust -
sometimes renaming fails because the deleted adapter name
might present in the registry even though adapter is not shown
anymore in enumeration.

Ensure that adapter name doesn't contain disallowed symbols.

Use --hwid ovpn-dco by default and update documentation.

Change-Id: I270f679505c90ef78a5afbad1e05219f166be089
Signed-off-by: Lev Stipakov <lev@openvpn.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1374
Message-Id: <20251116121146.4067-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg34455.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>