Add form styles and update button classes for consistency

- Introduced a new CSS file for form styles (forms.css) to enhance form layout and design.
- Removed deprecated button styles from imports.css and updated button classes across templates to use the new utility classes.
- Updated various templates to reflect the new button styles, ensuring a consistent look and feel throughout the application.
- Refactored form-related styles in main.css and removed redundant styles from projects.css and scenarios.css.
- Ensured responsive design adjustments for form actions in smaller viewports.

templates/projects/form.html

@@ -26,8 +26,8 @@
         <p class="text-muted">Provide core information about the mining project.</p>
       </div>
       <div class="header-actions">
-        <a class="btn" href="{{ cancel_url }}">Cancel</a>
-        <button class="btn primary" type="submit">Save Project</button>
+  <a class="btn btn--secondary" href="{{ cancel_url }}">Cancel</a>
+  <button class="btn btn--primary" type="submit">Save Project</button>
       </div>
     </header>
 
@@ -58,8 +58,8 @@
     </div>
 
     <div class="form-actions">
-      <a class="btn" href="{{ cancel_url }}">Cancel</a>
-      <button class="btn primary" type="submit">Save Project</button>
+  <a class="btn btn--secondary" href="{{ cancel_url }}">Cancel</a>
+  <button class="btn btn--primary" type="submit">Save Project</button>
     </div>
   </form>
 {% endblock %}