license: Change hatohol license from GPLv2 to LGPLv3.

We change hatohol license from GPLv2 to LGPLv3.
- To accept maximum collaborators.
- To allow (indirect) linkage with OpenSSL via MariaDB.

Signed-off-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: Hiroshi Hatake <hatake@clear-code.com>
Signed-off-by: Hiroshi Hatake <cosmo0920.oucc@gmail.com>