[WIP] Add support for installing plugins & themes by uploading ZIP files

[LukeTowers]

This PR adds the ability to install plugins & themes from ZIP archives, either uploaded through the backend or via the plugin:install and theme:install commands.

Currently working:

• plugin:install plugin(s).zip - supports single plugin, single plugin nested, multiple plugins no authors, multiple authors, and an entire plugins directory

TODO:

• Support theme:install theme(s).zip - support single theme, multiple themes
• "Upload Plugin" installer GUI - support all sources currently supported in CLI, user uploads a zip folder and then the plugins are installed and migrated using the same process that handles installing multiple plugins from the marketplace right now
• "Upload Theme" installer GUI - support same sources as CLI, user uploads a zip folder and then the themes are installed
• Testing

Eventually this will also play into the work in #967 and our overall marketplace support in general.

Work in progress.

[mjauvin]

@LukeTowers Maybe we should move this to 1.2.8 and cut that long overdue release?

[austinkregel]

👋🏻 Hello there, I'd like to help contribute to this effort. Would the team accept pull requests to this branch to help get things up and running?

At the moment due to the requirements of the winter/wn-blog-plugin:dev-main branch currently has ~1.2.8 which prevents a composer install unless you decrease the version of winter/wn-blog-plugin:~2.1.0 appears to at least let me install the required plugins.

[LukeTowers]

@austinkregel definitely! You can get around that issue by requiring winter/wn-backend-module: dev-wip/support-uploading-packages as 1.2.8 in your composer.json file.

[austinkregel]

@LukeTowers between this PR and this PR, which one would be preferred to work on? 👀

[LukeTowers]

@austinkregel definitely #1259. I think some of the changes from this one might need to be integrated back into the other one, but the main work is being done on #1259