[docs] Downgrade Doxygen to 1.10.0 and update theme (#6978)

Fixes mobile
Requires re-excluding memory for search
Set new doxygen options required by doxygen-awesome theme

docs/.styleguide

@@ -0,0 +1,3 @@
+generatedFileExclude {
+  theme.css
+}

docs/build.gradle

@@ -45,11 +45,13 @@ doxygen {
     // Doxygen binaries are only provided for x86_64 platforms
     // Other platforms will need to provide doxygen via their system
     // See below maven and https://doxygen.nl/download.html for provided binaries
+    // Ensure theme.css (from https://github.com/jothepro/doxygen-awesome-css) is compatible with
+    // doxygen version when updating
 
     String arch = System.getProperty("os.arch");
     if (arch.equals("x86_64") || arch.equals("amd64")) {
         executables {
-            doxygen version : '1.12.0',
+            doxygen version : '1.10.0',
             baseURI : 'https://frcmaven.wpi.edu/artifactory/generic-release-mirror/doxygen'
         }
     }
@@ -142,6 +144,9 @@ doxygen {
         exclude 'units/**'
     }
 
+    //TODO: building memory docs causes search to break
+    exclude 'wpi/memory/**'
+
     exclude '*.pb.h'
 
     // Save space by excluding protobuf and eigen
@@ -163,10 +168,12 @@ doxygen {
     extract_static true
     file_patterns '*'
     full_path_names true
+    full_sidebar false
     generate_html true
     generate_latex false
     generate_treeview true
     html_extra_stylesheet 'theme.css'
+    html_colorstyle 'LIGHT'
     html_timestamp true
     javadoc_autobrief true
     project_name 'WPILibC++'