Relicense PEcAn.settings and shiny/SDAdashboard as BSD-3

[infotroph]

Description

Updating the license files upon realizing we have agreement from all the contributors to these packages, who I will tag below to say: Thank you for all your work on these packages and for agreeing to the change! We have your agreement on file, so you don't have to take any further action for this PR.

settings: @Sweetdevil144 @ashiklom @helge22a @bailsofhay @infotroph @dlebauer @DongchenZ @Aariq @para2x @meetagrawal09 @mdietze @robkooper @moki1202 @serbinsh @nanu1605 @tonygardella @araiho @istfer @hangyakuzero @rahul799

SDAdashboard: @helge22a @para2x @rahul799

[Eagle-eyed readers will notice that I named my branch wrong; the uncertainty package is not changed here and is still waiting for more contributors to weigh in 😄]

Motivation and Context

Review Time Estimate

• Immediately
• Within one week
• When possible

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• My name is in the list of CITATION.cff
• I have updated the CHANGELOG.md.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.