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

@@ -267,13 +267,13 @@
 								<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">{$t('register.availabilities')}:</p>
-									<ul class="text-sm text-gray-600">
+									<ul class="text-xs text-gray-500">
 										{#each tutor.availabilities as availability}
 											<li>{availability.day}: {availability.start} - {availability.end}</li>
 										{/each}
 									</ul>
 								{:else}
-									<p class="text-sm text-gray-500 mt-1">{$t('register.noAvailabilities')}</p>
+									<p class="text-xs text-gray-500 mt-1">{$t('register.noAvailabilities')}</p>
 								{/if}
 								{#if tutor.calcom_link}
 									<a