Share chat url

Modal for video owner (and instance's moderators) that allows to generate a link to the chat. So you can - for example - obtain the url to use for OBS integration.
WIP

client/videowatch/button.ts

@@ -0,0 +1,56 @@
+import type { SVGButton } from './buttons'
+import { logger } from './logger'
+
+interface displayButtonOptions {
+  buttonContainer: HTMLElement
+  name: string
+  label: string
+  callback: () => void | boolean
+  icon?: SVGButton
+  additionalClasses?: string[]
+}
+
+function displayButton ({
+  name,
+  label,
+  callback,
+  buttonContainer,
+  additionalClasses,
+  icon
+}: displayButtonOptions): void {
+  const button = document.createElement('a')
+  button.classList.add(
+    'orange-button', 'peertube-button-link',
+    'peertube-plugin-livechat-button',
+    'peertube-plugin-livechat-button-' + name
+  )
+  if (additionalClasses) {
+    for (let i = 0; i < additionalClasses.length; i++) {
+      button.classList.add(additionalClasses[i])
+    }
+  }
+  button.onclick = callback
+  if (icon) {
+    try {
+      const svg = icon()
+      const tmp = document.createElement('span')
+      tmp.innerHTML = svg.trim()
+      const svgDom = tmp.firstChild
+      if (svgDom) {
+        button.prepend(svgDom)
+      }
+    } catch (err) {
+      logger.error('Failed to generate the ' + name + ' button: ' + (err as string))
+    }
+
+    button.setAttribute('title', label)
+  } else {
+    button.textContent = label
+  }
+  buttonContainer.append(button)
+}
+
+export {
+  displayButtonOptions,
+  displayButton
+}