fix(plugins/unocss): replace dynamic URL import with base64-encoded ES module

[miguelrk]

Follow-up of https://github.com/netzo/netzo/pull/139.

It appears that Subhosting is failing to resolve static-analyzable dynamic imports which might be the underlying casue of why the dynamic import of the uno.config.ts file breaks deployments, since it works locally. This PR updates the unocss plugin to load the uno.config.ts from its base64-encoded ES module (like it already does for the client-side CSR script), instead of importing it from a fileURL. This because the file URL is somehow being resolved to "https://deno.land/home/mrk/playground/crm/uno.config.ts", thus throwing the following error

error: Uncaught (in promise) TypeError: Module not found "https://deno.land/home/mrk/playground/crm/uno.config.ts".
          config = (await import(configURL)).default;
                    ^
    at async Object.configResolved (https://deno.land/x/netzo@0.4.47/plugins/unocss/plugin.ts:201:21)
    at async Promise.all (index 3)
    at async getServerContext (https://deno.land/x/fresh@1.6.5/src/server/context.ts:77:5)
    at async dev (https://deno.land/x/fresh@1.6.5/src/dev/dev_command.ts:57:17)
    at async file:///home/mrk/playground/crm/dev.ts:6:1