Adding test to ensure the wasm binaries size don't get too large

[cecton]

As a web framework Yew needs to ensure future additions to the framework will have a good or a minimal impact on the size of the output wasm binaries. This is because we don't know where or how an app using Yew will be used. It could be used for a web site. Any extra bytes count if we don't want to boat the internet even more than it currently is.

The solution here would be to add a test to save and compare the size of the examples app we provide. Any difference in size should make the test fail so the developer will need to update the saved size to match the size of the wasm binaries generated in their branch. This will make the review process easier as it can make it clear to the reviewer that a change got impact on the size of the binary.

Related to #2396