Small package cleanup

[realityking]

Here's some cleanup/some simplifications:

• Remove support for bower - it's well an throughly deprecated
• Remove support for composer - there's only ~2 installs per day and those are old versions (source)
• Remove .npmignore. It wasn't used anyway as the package.json specifies "files", which takes precedence.
• Add Node.js 14 to the build matrix

Dropping composer and bower will allow making some more invasive changes to the build artefacts that npm supports but that are a poor fit for bower and composer.