Add header styled like Biosphere Capital site

- Adds Biosphere Capital logo
- Adds dummy nav with no dropdown links

frontend/src/assets/styles/header.scss

@@ -0,0 +1,18 @@
+.top-header {
+    padding-bottom: 3.2vw;
+}
+
+.header-logo {
+    max-height: 110px;
+}
+
+.nav-link {
+    color: white !important;
+    font-weight: 200;
+    font-size: 16px !important;
+    padding: 0px !important;
+}
+
+.nav-item {
+    margin-left: 26.8667px;
+}

frontend/src/assets/styles/main.scss

@@ -1,8 +1,13 @@
 @import "./theme.scss";
+@import "./header.scss";
 
 // Core styles here...
 .App {
     font-family: $primary-font;
     color: $text-color-primary;
     background-color: $background-color-primary;
+    padding-top: 3.2vw;
+    padding-left: 3vw;
+    padding-right: 3vw;
+    padding-bottom: 3.2vw;
 }

frontend/src/assets/styles/theme.scss

@@ -1,4 +1,4 @@
-@import url('https://fonts.googleapis.com/css2?family=Poppins&display=swap');
+@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@200;400&display=swap');
 
 // COLOURS
 $background-color-primary: #000000;