Since we'll only look in the plugin directory, and not from multiple
sources now, for installing/listing plugins, we can simplify the
structures which used to accept multiple directories so they only accept
one.
Since we're removing the alternative plugin installation directories in
favour of only supporting installing them in the PACKER_PLUGIN_PATH
directory, we only return one directory when getting the known plugin
directories.
Since this feature is no longer something we plan to activate later, as
it contradicts with our efforts to remove bundled plugins, and
encouraging users to move to either manually installing plugins, or
managing them through `packer init', we clean-up the code for this
feature.
* Updating the license from MPL to Business Source License
Going forward, this project will be licensed under the Business Source License v1.1. Please see our blog post for more details at https://hashi.co/bsl-blog, FAQ at https://hashi.co/license-faq, and details of the license at www.hashicorp.com/bsl.
* Update copyright file headers to BUSL-1.1
---------
Co-authored-by: hashicorp-copywrite[bot] <110428419+hashicorp-copywrite[bot]@users.noreply.github.com>
