Refactor LICENSE.md to make it scanner friendly (#41095)
Create THIRDPARTY.md to hold license information for all code not covered by the main MIT license. This format allows for automated scanning and categorization of Julia's license. The licenses were broken up this way because this is the format that many automated license scanners (including GitHub).
(cherry picked from commit 161e38496dff86873c595428e4da12620e528c57)