feat: make filter panel sticky to the top of the page (#398)

Fixes #389 
<img width="1538" alt="Screenshot 2023-09-18 at 12 10 26 PM"
src="https://github.com/TBD54566975/ftl/assets/51647/e5a4b025-9616-444c-924f-696e71485937">

console/client/src/features/timeline/TimelinePage.tsx

@@ -23,9 +23,11 @@ export const TimelinePage = () => {
       <PageHeader icon={<ListBulletIcon />} title='Events'>
         <TimelineTimeControls onTimeSettingsChange={handleTimeSettingsChanged} />
       </PageHeader>
-      <div className='flex h-full'>
-        <TimelineFilterPanel onFiltersChanged={handleFiltersChanged} />
-        <div className='flex-grow'>
+      <div className='flex' style={{ height: 'calc(100% - 44px)' }}>
+        <div className='sticky top-0 flex-none overflow-y-auto'>
+          <TimelineFilterPanel onFiltersChanged={handleFiltersChanged} />
+        </div>
+        <div className='flex-grow overflow-y-scroll'>
           <Timeline timeSettings={timeSettings} filters={filters} />
         </div>
       </div>

console/client/src/layout/Layout.tsx

@@ -8,8 +8,8 @@ export const Layout = () => {
     <div className='flex h-screen'>
       <Navigation />
 
-      <main className='flex-1 overflow-hidden'>
-        <section className='overflow-y-auto h-full'>
+      <main className='flex-1 overflow-y-auto'>
+        <section className='h-full relative'>
           <Outlet />
         </section>
       </main>