Remove StaticServer extension

[abose]

• Static servers are not possible with the current web application framework
• Remove StaticServer default extension.

notes

It is used for the experimental multi-browser live preview feature. But the multi-browser feature will not work anyway within browsers with the current web tech.

A possible option is to have a backend server from core.ai to proxy the requests(either at core.ai or phoenix agent locally installed(defeating the purpose of a true web app)), but it might be less instant, need to evaluate alternatives.