feat: use standard template for ccache file

Default SSSD template for ccache file is /tmp/krb5cc_%U_XXXXXX, where
XXXXXX is a suffix that will be interpreted by mkstemp(3) to create a
unique file name, while the standard configuration of the libkrb5
library is `/tmp/krb5cc_%U`.

To guarantee compatibility with the existing system, we force the use
of the standard model in SSSD.

etc/sssd/sssd.conf

@@ -36,6 +36,8 @@ krb5_renewable_lifetime = 7d
 krb5_renew_interval = 30m
 krb5_use_kdcinfo = true
 krb5_kdcinfo_lookahead = 5:2
+krb5_ccachedir = /tmp
+krb5_ccname_template = FILE:%d/krb5cc_%U
 dns_discovery_domain = S-FT-FR-EBU._sites.ad.francetelecom.fr
 #
 chpass_provider = none