Update to upstream version 3.7.0

Detailed log:

• Update audio/grip to 3.7.0
• Fix LICENSE
• Convert to USES=localbase
• Remove --disable-nls which does nothing
• Trim down the encoders list defined in src/gripcfg.c to those which we have ports for and fix a pre-existing offset problem that arose from removing one the encoders from the list. Specfically, the "xingmp3enc" encoder was removed, but ginfo->selected_encoder was not changed in src/grip.c. This caused the program to point to the flac encoder as the default instead of oggenc and overwrote the flac settings with the settings for oggenc.

PR: 227336
Submitted by: jhale
Differential Revision: https://reviews.freebsd.org/D14997