ui: Increase the width of app and system listings

- Increase the width of the containers that hold home cards, app cards, system
cards, and help cards. This helps in:

  - Showing system page layout better with wider cards for each item.

  - Showing more apps in the app page. This does not decrease the readability in
  the same way that increasing the size of the paragraph does beyond a certain
  point.

- Also increase the width of the navbar to make it appear consistent.

- Other containers such as content container remain at the same width.
Increasing this width would make a reading a paragraph harder.

- Behavior is mobile layouts is unchanged.

Tests:

- Test that apps, system, home and help views show cards in a wider layout.

- Success/error messages shown in apps, system, home and help views are narrow
and are not effected.

- In home and help:index pages (reached when clicking help icon without JS), the
icons are wide but the content is narrow.

- Individual app pages, confirmation pages, and help pages remain at the older
width.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

static/themes/default/css/main.css

@@ -313,10 +313,12 @@ html {
 }
 
 .container {
-  max-width: 1000px;
+    /* Same width as container-xxl in Bootstrap 5 */
+    max-width: 1320px;
 }
 
 .content-container {
+    max-width: 1000px;
     margin-bottom: 1.25rem;
 }