fix: lodash imports to use tree shaking to reduce bundle size

[ceremonious]

I've been trying to reduce our bundle size and I saw that rich-markdown-editor is importing the entirety of lodash, which is a big library. These changes should help reduce the size.

[thenanyu]

hey @ceremonious — I'm under the impression that the lodash maintainers recommend you do not do this, per https://lodash.com/per-method-packages

per method packages are being removed in v5

[tommoor]

@thenanyu that article is referring to lodash.pick style, not lodash/pick which is okay.

I'm happy to merge this one, it hasn't been an issue in our main consuming repo because we use the babel plugin to make sure the minimum version of lodash is transpiled but I understand that not ever host app should have to do that.