[YSQL] Consider pre-creating the sequences namespace and table

[m-iancu]

Jira Link: DB-1330
As mentioned in #4890 the metadata for sequences (last val, is_called, etc) is stored in a dedicated system table (sequences_data) that is created (along with its namespace system_postgres if needed) the first time a sequence of created.
As a follow-up to #4890 we should consider pre-creating these when initializing the cluster in the future to improve reliability and usability (e.g. avoid further issues with concurrent create sequence, or the first create sequence taking longer than expected).

cc @hectorgcr