misc: Stop tracking clickhouse schema (#2309)

## Context

Today the `db/clickhouse_schema.rb` is tracked in git. This file
contains "sensitive" data like the Kafka URL and password (for local
env).

In order to avoid comiting these sensitive data, a `clickhouse:filter`
rake task was added to obfuscate the values.

As CI tasks are performing the full clickhouse migrations, it appears
that the shema.rb file is actually not mandatory at all and could be
removed from the git repository.

## Description

This PR:
- Removes the `db/clickhouse_schema.rb` file
- Add the  `db/clickhouse_schema.rb` in the untracked files
- Remove the `clickhouse:filter` rake task

.github/workflows/spec.yml

@@ -63,7 +63,7 @@ jobs:
         run: bin/rails db:schema:load:primary
       - name: Set up Clickhouse database schema
         run: bin/rails db:migrate:clickhouse
-      - name: Set up Clickhouse database schema
+      - name: Dump Clickhouse database schema
         run: bin/rails db:schema:dump:clickhouse
       - name: Run tests
         run: bundle exec rspec

.gitignore

@@ -23,6 +23,7 @@
 !/tmp/storage/
 !/tmp/storage/.keep
 db/events_schema.rb
+db/clickhouse_schema.rb
 
 .env
 .byebug_history