build: Bundling is extremely slow and doesn't support debugging

[dwmkerr]

Bundling has been challenging for this extension. Currently I am not happy with rollup.js as the bundler as the real-time updates are very slow, require extra heap memory for node (see ./package.json and still do not support debugging. Options for bundlers and current status is below. It is possible that the mermaid.js issues will be resolved if the root cause of https://github.com/parcel-bundler/parcel/issues/8935 is fixed in mermaid.

Rollup.js

• Con: Very slow for real-time updates
• Con: Extra heap space needed
• Con: debugging / sourcemaps do not work: https://github.com/crxjs/chrome-extension-tools/issues/691

Parcel

• Pro: simple, minimal API and dependencies
• Con: Fails to bundle mermaid.js correctly: https://github.com/parcel-bundler/parcel/issues/8935

Webpack

• Pro: most popular / documented / well supported of the options it seems
• Con: Fails to bundle mermaid.js correctly, as tested at https://github.com/dwmkerr/parcel-mermaid-import-issue

Webpack

• Pro: very simple setup
• Pro: very fast reload
• Pro: bundles mermaid.js without issues
• Con: Sourcemaps don't seem to work (https://github.com/dwmkerr/parcel-mermaid-import-issue)
• Con: Build seems to fail with stack overflow, suggesting memory/perf issues: https://github.com/dwmkerr/parcel-mermaid-import-issue

[dwmkerr]

Note: the latest version of the code using webpack seems to work properly