Implement CSS-only input toggling, refactor related forms

UX/Translation changes:

- new teams: remove redundant tooltips that don't add meaningful information
  - move general information to table fieldset
- new teams: rename "general" to "custom" access for clarity
- new teams: show labels beside options on mobile

Accessibility:

- semantic form elements allow easier navigation (fieldset, mostly)
- improve better labelling of new teams table
- fix accessibility scan issues
- TODO: the parts that "disable" form elements were not yet touched and
  are not really accessible to screenreaders

Technical:

- replace two JavaScript solutions with one CSS standard
- implement a simpler grid (.simple-grid)
- simplify markup
- remove some webhook settings specific CSS

Testing:

- check more form content for accessibility issues
- but exclude tooltips from the scan :(
- reuse existing form tests from previous PR

web_src/js/features/comp/WebHookEditor.js

@@ -1,27 +1,11 @@
 import {POST} from '../../modules/fetch.js';
-import {hideElem, showElem, toggleElem} from '../../utils/dom.js';
+import {toggleElem} from '../../utils/dom.js';
 
 export function initCompWebHookEditor() {
   if (!document.querySelectorAll('.new.webhook').length) {
     return;
   }
 
-  for (const input of document.querySelectorAll('label.events input')) {
-    input.addEventListener('change', function () {
-      if (this.checked) {
-        showElem('.events.fields');
-      }
-    });
-  }
-
-  for (const input of document.querySelectorAll('label.non-events input')) {
-    input.addEventListener('change', function () {
-      if (this.checked) {
-        hideElem('.events.fields');
-      }
-    });
-  }
-
   // some webhooks (like Gitea) allow to set the request method (GET/POST), and it would toggle the "Content Type" field
   const httpMethodInput = document.getElementById('http_method');
   if (httpMethodInput) {