feat(bot): implement conversation flow for start command

add conversation handler for start command with name input and welcome message
update locales for new conversation flow
add @grammyjs/conversations dependency

apps/bot/src/conversations/start.conversation.ts

@@ -0,0 +1,23 @@
+import { Conversation, createConversation } from '@grammyjs/conversations';
+import { BotContext } from '../types';
+import { ConversationSlug } from './consts';
+
+async function enterConversation(conversation: Conversation, ctx: BotContext) {
+  const askNameText = await conversation.external((ctx: BotContext) =>
+    ctx.t('start-ask-name')
+  );
+
+  await ctx.reply(askNameText);
+
+  const { message } = await conversation.waitFor('message:text');
+  const welcomeText = await conversation.external((ctx: BotContext) =>
+    ctx.t('start-welcome', { user: message.text })
+  );
+
+  await ctx.reply(welcomeText);
+}
+
+export const startConversation = createConversation(
+  enterConversation,
+  ConversationSlug.START
+);