Package libshell: Information

- shell-ini-config changes:
  + Fix empty lines at EOF (ALT#27974).
  + Indentation in the ini-file can be configured by
    shell_ini_config_prefix (ALT#27915).

- Packaged -single subpackage with all libshell functions bundled into
  the single shell-lib file.
- New utilities:
  + shell-cmdline: New functions to parse /proc/cmdline.
- shell-error changes:
  + Add optional timestamp to messages.
- shell-run changes:
  + Add SCRIPT_ERROR_FATAL var to control execution interrupt
    on error (thx Ildar Mulyukov).
  + Fix execution order of scripts in run_scripts() (thx Ildar Mulyukov).
- shell-args changes:
  + Add opt_check_exec().
- Other changes:
  + Generate SYMS and DEPS files.

- shell-ini-config changes (ALT#25946):
  + Fix comment formatting (thx Vladislav Zavjalov);
  + Add section if it is not exists (thx Vladislav Zavjalov);
  + Fix error at adding values to the last section (thx Vladislav Zavjalov);
  + Fix error of adding values into incorrect sections (thx Vladislav Zavjalov).