[Feature] UI Plugin dependency loading

[feederbox826]

Is your feature request related to a problem? Please describe.
no

Describe the solution you'd like
In replacing userscripts with ui plugins, script libraries and CSS imports have to be downloaded alongside plugins and injected into the /javascript and /css files

alongside CSP allowed domains, additional properties for imported scripts (corresponding to CSP: script-src) and imported stylesheets (CSP:style-src) can be added, and injected as <style> and <script> blocks

Describe alternatives you've considered
Currently the files are being downloaded unminfied and stored in the plugin's repo but this leaves room for malicious actors uploading minified, modified code.

Additional context
Originally discussed in Userscript -> JS plugin port thread on discord
original CSP PR #2108

[feederbox826]

closed in #4256

[DogmaDragon]

I'm pretty sure it was addressed in #4260.