Registration flow

Now, the tutor can set a general "Bio' during the registration process (/tutor/register/). The 'Bio' component is located in step 3 (Informations) of the registration flow.

Update (22/02):

• Successfully merged registration flows for learners and tutors into a single flow

frontend/src/routes/register/+page.svelte

@@ -264,7 +264,7 @@
 								<p class="text-sm text-gray-600">
 									First Language: {tutor.home_language || 'Not specified'}
 								</p>
-								<p class="text-sm text-gray-500 mt-1">{tutor.bio || 'No bio available.'}</p>
+								<p class="text-xs text-gray-500 mt-1">{tutor.bio || 'No bio available.'}</p>
 								{#if tutor.availabilities?.length > 0}
 									<p class="text-sm text-gray-800 mt-2">{$t('register.availabilities')}:</p>
 									<ul class="text-sm text-gray-600">