Shrink bundle size

Current size benefits:

Commit	index.js	charts.js	all	message
444546b1	480K dist/index.js	268K dist/charts.js	4.4M dist	Baseline
558ad34d	412K dist/index.js	252K dist/charts.js	4.0M dist	build(rollup): Update rollup-plugin-vue
52b3ca90	396K dist/index.js	240K dist/charts.js	3.8M dist	refactor(bootstrap-vue): Use src instead of built esm modules
914cb82d	268K dist/index.js	156K dist/charts.js	2.7M dist	build(rollup): Externalize more dependencies
b93cb4c8	268K dist/index.js	100K dist/charts.js	2.4M dist	build(charts): Include popover component from gitlab-ui
e84615dd	256K dist/index.js	96K dist/charts.js	2.3M dist	build(rollup): Run rollup in production mode