Suggested changes

Changes proposed in this pull request:

refactor: get plugins configuration.
- we decided to use /plugin/{pluginName}/config route
- the plugins are requested on main page load, also when user is not logged in. This approach is preferred for future support of plugins that do not require user login. The plugins that require user login should return empty array (no options).
refactor: user menu hook moved inside the component to avoid calls when user is not logged in
fix: create license files for documentation markdown files
tests: create svg component test and fix muiSnackbar test

How to test:

make start to build app and generate test data
RSD app should work without any problems. No plugins are defined at this stage.
modify settings.json to include some imaginary plugins
rebuild app.
Open home page. Confirm that warning is issued in the logs about missing plugins but the RSD app should work without problems
If you can, test with real plugin that should change user and edit software menus.

PR Checklist:

research-software-directory / RSD-as-a-service