Update various dependencies to newer versions, including h5web.

Updates a couple of the core dependencies, notably react-scripts and h5web (#900 (closed)), to a newer version. Almost all dev dependencies are also upgraded. This makes the linting more sensitive/accurate, so various linting errors needed to be fixed, and some less relevant warnings have been disabled. These changes should pave the way for an upgrade of the react library.

Note, requires a more recent version of node than previously used in the CI docker, and also more recent than what comes with the current standard installation of e.g. Ubuntu.