Update LICENSE to BSD 3-Clause

[cryolune]

Description

This PR updates the License of PecAn Status Board to BSD 3-Clause

Motivation and Context

Review Time Estimate

• Immediately
• Within one week
• When possible

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 LICENSE
• 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.

[cryolune]

@infotroph Could you please review the changes in the license?

[infotroph]

Thanks for doing this! While we're at it, let's bring the license format in line with the CRAN requirement for R packages, (which is kinda weird compared to packages in most other languages, TBH). Following the format recommended by usethis, can you please:

• In DESCRIPTION, change License: NCSA to License: BSD_3_clause + file LICENSE.
• Move the actual license text from LICENSE to LICENSE.md
• Confirm that .Rbuildignore contains a line matching LICENSE.md so that it's provided to everyone who downloads the source code but is not included in the installed package.
  • It is a CRAN requirement to not include the license text in the built package; I disagree with this but we follow it anyway.
  • My understanding of their reasoning is that R provides built-in ways to read the text of all the standard licenses, so providing another copy of it in every package is super-redundant even though each individual copy is small.
• Edit the LICENSE file to contain only the following text (think of this as a template to fill in the blanks in the BSD license)

  YEAR: 2024
  COPYRIGHT HOLDER: PEcAn Project
  ORGANIZATION: PEcAn Project, authors affiliations