When using HTTPS, the phones use SSLv3, and since SSLv3 support has been
removed on XiVO on the 443 port, the directory is not accesible anymore
with the default configuration on the Aastra.

Other phones (Snom, Yealink) use HTTP to interact with the remote
directory. The Aastra phones downloads its configuration file using
HTTP. The phone doesn't do certificate verification. The remote
directory is accessible to anyone with an allowed IP address.

If someone really wants to use HTTPS to interact with the remote
directory, a custom template can always be used.

default parameter values were changed on all cisco-spa plugins.

It's not the same as for the other SPA.

Some parameters were duplicated.

They don't hurt but they are not necessary.

Most ATA are used to connect analog faxes. Parameters changed here ease
fax integration.

preparing to change default values for ATA devices while leaving those of phone
devices untouched

This plugin doesn't have support for the 6757iCT and 9480iCT because
the 3.3.1 SP4 firmware is not available for these two models.

So that some fixes that have been made to the W52P plugin are also
present for other plugins.

Remove other W52P plugins.

On XiVO, when synchronizing a SCCP phone, this is actually done via
xivo-sysconfd.