`cobj-idx unlock` and `cobj-idx migrate` should handle multiple files

[yutaro-sakamoto]

In the latest version, cobj-idx unlock and cobj-idx migrate handles a single file at once.

cobj-idx migrate <indexed file>
    Migrate the indexed file whose version is older than 1.1.12 to the latest version.

cobj-idx unlock <indexed file>
    Unlock all locks of the indexed file.

Both cobj-idx unlock and cobj-idx migrate should be able to handle multiple files at once.
These commands are implemented in libcobj/app/src/main/java/jp/osscons/opensourcecobol/libcobj/user_util/indexed_file/IndexedFileUtilMain.java