Better babel plugin import integration

[plrthink]

This change tends to make ibot has better integration with bable-import-plugin, which would help users loading resources on demand. Although we have supported it already, but not perfectly. The reason is we were using named export somewhere in this codebase but bable-plugin-import has the limitation towards this since it can only (on my perspective) find the right entry module witch default export, which means users would right the entire path to import the module they want, both js and css.
That would also be erorr prone because they may forget to import the styles.

So I changed the export on the surface to the default export, this change is a break change cause it requires users to tweak their code some cases like form component.

And shame on me, I broke the SEMVER again for publishing the wrong version to the wild.

[plrthink]

啊 失误了 应该手动来 rebase