LU-18753 obdclass: remove obsolete dt functions

LU-18753 obdclass: remove obsolete dt functions

Remove:

dt_path_parser()
dt_store_resolve()
dt_store_open()
dt_reg_open()
dt_find_entry()
typedef dt_entry_func_t

These are not called anywhere.

Fixes: 29e98f581ab6 ("LU-2886 obdclass: remove obsoleted md_local_file.c")
Fixes: 29adfde10ff2 ("LU-2886 mdd: create local files using local_storage lib")
Fixes: 90d8e7fd2874 ("Land b_head_interop_disk  on HEAD (20081119_1314)")
Test-Parameters: trivial
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: I5a79f665104c0526db1e328c0e682ce85b592028
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58227
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Aurelien Degremont <adegremont@nvidia.com>
Reviewed-by: Max Wang <wamax@amazon.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>