audio/grip: Update to 3.7.0

[jhale]

Summary

• 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.

Test Plan

Poudriere build tests done on:
10.4-i386
11.1-amd64
12.0-amd64

Basic runtime test done on 12.0-amd64.

[riggs]

This is very good! Thanks for addressing the issues with grip!