ENH: Navbar image is backlink to root directory.

src/core/xsl/navbar.xsl

@@ -55,7 +55,7 @@
             <span class="icon-bar"></span>
             <span class="icon-bar"></span>
           </button>
-          <a class="navbar-brand">
+          <a class="navbar-brand" href="/">
             <xsl:element name="img">
               <xsl:if test="'${BUILD_NAVBAR_BRAND_NAME}' != ''">
                 <xsl:attribute name="class">caosdb-logo</xsl:attribute>