ADD support for .sid file generation and update

[HanzlikPetr]

Adds Schema Item Identifier (SID) file support per RFC 9595, enabling
libyang to generate, update, and extend .sid files for YANG modules.
The change spans the library (new ietf-sid-file module and
printer_sid.c) and the yanglint tool (new sid command).

Library (public API in tree_schema.h):

• lys_sid_gen() - generate a new .sid file
• lys_sid_update() - update a previous .sid file (reuse SIDs, mark removed items "obsolete", bump sid-file-version)
• lys_sid_range_add() - append a new assignment range
• LYS_SID_FILE_STATUS enum (UNPUBLISHED / PUBLISHED)

yanglint sid command (interactive and -g/--sid non-interactive):

• generate EP:SIZE [published]
• update <prev.sid> [published]
• range-add EP:SIZE <prev.sid>