This fix tries to address the issue raised in #23055.
Currently `docker search` result caps at 25 and there is
no way to allow getting more results (if exist).
This fix adds the flag `--limit` so that it is possible
to return more results from the `docker search`.
Related documentation has been updated.
Additional tests have been added to cover the changes.
This fix fixes#23055.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>