Use correct license and consistent metadata in package.json files

[SergeyBiryukov]

Got a warning when running npm install for wporg-developer theme:

npm WARN wporg-developer@ license should be a valid SPDX license expression

GPLv2 or later is not a valid ​SPDX license identifier, GPL-2.0+ is.

On a related note, there are some inconsistencies in name, description, and author entries in package.json files across different projects:

• wporg:

  "name": "wporg"
  "description": "Theme for WordPress.org"
  "author": "wordpressdotorg"
  "license": "GPL-2.0"
  

• wporg-developer:

  "name": "wporg-developer",
  "description": "Theme for developer.wordpress.org",
  "author": "wordpressdotorg",
  "license": "GPLv2 or later",
  

• wporg-plugins:

  "name": "wporg-plugins",
  "description": "Theme for the WordPress.org Plugin Directory",
  "author": "wordpressdotorg",
  "license": "GPL-2.0",
  

• wporg-support:

  "name": "wporg-support",
  "description": "Support Forums",
  "author": "wordpressdotorg",
  "license": "GPL-2.0",
  

• wporg-themes:

  "name": "WordPress.org-Themes"
  "description": "Theme for the WordPress.org themes directory."
  "author": "The WordPress.org Team"
  "license": "GPL-2.0+"
  

[coffee2code]

In 5068:

WP.org Theme: Use consistent SPDX license identifier in package.json.

Props SergeyBiryukov.
See #2460.

[coffee2code]

In 5069:

Theme Directory Theme: Use consistent name, description, and author values in package.json.

Props SergeyBiryukov.
See #2460.

[coffee2code]

In 5070:

Support Theme: Use valid SPDX license identifier and consistent description format in package.json.

Props SergeyBiryukov.
See #2460.

[coffee2code]

In 5071:

Plugin Directory Theme: Use consistent license identifier and description format in package.json.

Props SergeyBiryukov.
See #2460.

[coffee2code]

In 5072:

developer.wordpress.org: Use valid SPDX license identifier and consistent description format in package.json.

Props SergeyBiryukov.
Fixes #2460.

[SergeyBiryukov]

@coffee2code: wporg-main was added in [4885], needs the same fix as in [5068] (GPL-2.0+).

[coffee2code]

In 5073:

Main Theme: Use consistent license identifier in package.json.

Props SergeyBiryukov.
See #2460.

[coffee2code]

In 5074:

Learn Theme: Use consistent license identifier and description in package.json.

See #2460.