(zotero) Add 64-bit installer (re-try)

[teknowledgist]

This adds the new install option for 64-bit Zotero and simplifies the update a bit. This is essentially the same PR as submitted -- and closed -- previously but the version has been updated and it is hopefully "cleaner".

Description

• Modified the update.ps1 to grab both 32-bit and 64-bit installer URLs, download the EXEs and replace the information in the VERIFICATION.txt file.
• Modified chocolateyinstall.ps1 to install either 32-bit or 64-bit flavor of Zotero.
• Adjusted the VERIFICATION.txt file to better match the "standards" already in the repo.
• Added to chocolateyinstall.ps1 and chocolateyuninstall.ps1 files to work for both bit levels.
• Updated and re-arranged metadata in the .nuspec to match the order of a new package.
• Updated the LICENSE.txt file to match changes at the project.

Motivation and Context

32-bit Zotero works fine on 64-bit systems, but regularly pops up a dialog indicating that it's not the most efficient version for the environment. The upgrade from 32-bit to 64-bit is as simple as a re-install, so fixing this package to have both bit-levels was fairly straightforward.

How Has this Been Tested?

In Windows 11 and the official test environment. Installed the 32-bit-only, v7.0.9 package then upgraded to the local, modified v7.0.11 package from this PR with no trouble. Also installed the proposed package without upgrading. Uninstalls worked too.

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)
• Migrated package (a package has been migrated from another repository)

Checklist:

• My code follows the code style of this repository.
• My change requires a change to documentation (this usually means the notes in the description of a package).
• I have updated the documentation accordingly (this usually means the notes in the description of a package).
• I have updated the package description and it is less than 4000 characters.
• All files are up to date with the latest Contributing Guidelines
• The added/modified package passed install/uninstall in the Chocolatey Test Environment(https://github.com/chocolatey-community/chocolatey-test-environment/). Note that we don't support the use of any other environment.
• The changes only affect a single package (not including meta package).

[AppVeyorBot]

✅ Package verification completed without issues. PR is now pending human review