Fix some development warnings

[macabeus]

This PR fixes a couple of warnings when running the website.
I'm not fluent in Vue, but it seems to be running well.

• The first commit fixes this warning when building:

[@vue/compiler-sfc] defineProps is a compiler macro and no longer needs to be imported"

The fix is just removing all the defineProps imports.

• The second commit fixes this warning when rendering the /essential/validation.html page:

<tr> cannot be child of <table>

The fix is wrapping the <table> children with <tbody>. It seems that we already do it when building for production, but we need to explicitly write to do it in development mode too to suppress this warning.

The warning message is misleading btw (see vuejs/core#12088)

• The third commit fixes this warning from tsconfig.json:

Cannot write file '/Users/macabeus/elysiajs/documentation/postcss.config.js' because it would overwrite input file.ts
Cannot write file '/Users/macabeus/elysiajs/documentation/tailwind.config.js' because it would overwrite input file.ts

The fix is including these files in the exclude property from tsconfig.json.