Remove struct sss_krb5_cc_be and the remaining functions that reference
it as they are all unused now.

Resolves:
https://fedorahosted.org/sssd/ticket/2061

Only 2 types (FILE and DIR) need to precreate files or directories
on the file system, and the 2 functions were basically identical.

Consolidate all in one common function and use that function directly
where needed instead of using indirection.

Resolves:
https://fedorahosted.org/sssd/ticket/2061

This completely replaces the per-ccache-type custom code to remove old cacches
and instead uses libkrb5 base doperations (krb5_cc_destroy) and operating as
the user owner.

Resolves:
https://fedorahosted.org/sssd/ticket/2061

This tests dlopens and resolves all symbols to make sure there are no missing
symbols in our provider modules.

Recently support was added to use also libkrb5 style expansions that
uses a %{varname} type of template.

There are a number of templates we do not care/can't expand in sssd.
The current code misses tests and failed to properly preserve some of
the templates we do not want to handle.

Addiotionally in order to be future proof this patch treats unknown
templates as pass-through templates and defer any error checking to
libkrb5, so that sssd is consistent with how kinit would behave.

Resolves:
https://fedorahosted.org/sssd/ticket/2076

It is better to use standard constant for maximum value of type size_t,
instead of reinventing wheel with own defined constant SIZE_T_MAX

This patch replace string "SIZE_T_MAX" -> "SIZE_MAX"