ui: Don't bold titles in card lists

- Making most of text that is read in a page bold is useless. Emphasis should
instead be used for some text that should stand out of the rest of the text.

- The need to make the text bold goes away if the text color is not such a
lighter shade of gray. Reset this to the regular text color.

Tests:

- Observe changes in home, apps, system, and help index pages.

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

static/themes/default/css/main.css

@@ -576,11 +576,10 @@ a.menu_link_active {
 .card .nav-link {
     display: block;
     padding: 0.25rem;
-    color: #646464;
+    color: #212529;  /* Same as Bootstrap default color */
 }
 
 .card-title {
-    font-weight: 800;
     font-size: 1.25rem;
     padding: 0.75rem 0;
     margin-bottom: 0;
@@ -616,7 +615,6 @@ a.menu_link_active {
 .system-page .card-title {
     font-size: 1.125rem;
     font-style: normal;
-    font-weight: bold;
     overflow: hidden;
     white-space: nowrap;
     text-overflow: ellipsis;