Integrate some plugins with other plugins

- [ ] prevent duplicate plugins
```js
export default function(config) {
//...
const plugins = new Set(
options.plugins.map(its => its.name)
)
//...
return site => {
// ...
site.hooks.addXyzPlugin = plugin => {
if (!plugins.has(plugin.name)) {
// add plugin
}
}

site.hooks.hasXyzPlugin = plugin => plugins.has(
typeof plugin === "string" ? plugin : plugin.name
)

/** @example
```js
if (matchEsbuildConfig({
extensions, options: { target:"es5" }
})) addEsbuildPlugin(babel)
``` */
site.hooks.matchXyzConfig = config => {/* ... */}
}
}
```
---
- [ ] add plugin before/after other plugin
```js
site.hooks.afterXyzPlugin("plugin-a1", plugin({...}))

if (!site.hooks.hasXyzPlugin("plugin-a1"))
site.hooks.beforeXyzPlugin("plugin-b2", plugin({...}))
```
---
- [ ] babel for others
```js
import { babel as rollupBabel } from 'npm:@rollup/plugin-babel'

export default function(config) {
//...
return site => {
// ...
site.hooks.addRollupPlugin?.(rollupBabel(sameBabelConfig))
}
}
```
---
- [ ] rollup with others
```js
site.use(rollup())

import rollupEsbuild from "npm:rollup-plugin-esbuild"

site.hooks.addRollupPlugin(rollupEsbuild)
```