Add EULA to Windows interactive installer

Reference: https://www.electron.build/configuration/nsis#NsisOptions-license

Author: per1234

electron/build/resources/eula.txt

@@ -0,0 +1,5 @@
+Terms of Service
+
+By downloading the software from this page, you agree to the specified terms.
+
+The Arduino software is provided to you "as is" and we make no express or implied warranties whatsoever with respect to its functionality, operability, or use, including, without limitation, any implied warranties of merchantability, fitness for a particular purpose, or infringement. We expressly disclaim any liability whatsoever for any direct, indirect, consequential, incidental or special damages, including, without limitation, lost revenues, lost profits, losses resulting from business interruption or loss of data, regardless of the form of action or legal theory under which the liability may be asserted, even if advised of the possibility or likelihood of such damages.

electron/build/template-package.json

@@ -105,7 +105,8 @@
       "uninstallerIcon": "resources/icon.ico",
       "installerSidebar": "resources/installerSidebar.bmp",
       "uninstallerSidebar": "resources/installerSidebar.bmp",
-      "allowToChangeInstallationDirectory": true
+      "allowToChangeInstallationDirectory": true,
+      "license": "resources/eula.txt"
     },
     "dmg": {
       "icon": "resources/icon.icns",