Add pause control strategy for ClickHouse migrations

app/workers/click_house/events_sync_worker.rb

app/workers/concerns/click_house_worker.rb

...development/pause_clickhouse_workers_during_migration.yml

...elopment/wait_for_clickhouse_workers_during_migration.yml

...velopment/database/clickhouse/clickhouse_within_gitlab.md

doc/development/sidekiq/worker_attributes.md

ee/app/workers/click_house/ci_finished_builds_sync_worker.rb

...orkers/click_house/ci_finished_builds_sync_worker_spec.rb

lib/click_house/migration_support/errors.rb

lib/click_house/migration_support/exclusive_lock.rb

lib/click_house/migration_support/migration_context.rb

lib/click_house/migration_support/migration_error.rb

lib/click_house/migration_support/migrator.rb

lib/click_house/migration_support/sidekiq_middleware.rb

lib/gitlab/sidekiq_middleware.rb

lib/gitlab/sidekiq_middleware/pause_control.rb

...dleware/pause_control/strategies/click_house_migration.rb

.../lib/click_house/migration_support/exclusive_lock_spec.rb

...b/click_house/migration_support/migration_context_spec.rb

.../click_house/migration_support/sidekiq_middleware_spec.rb