sql: create jobs for truncated and dropped tables

[jseldess]

PR: https://github.com/cockroachdb/cockroach/pull/29993/commits

Creates a job for statements involving dropping or truncated tables, including
DROP DATABASE. The job is completed when the GC TTL expires and both table
data and ID is deleted for each of the tables involved.

Detailed running statuses are added to provide visibility to the
progress of the dropping or truncating of tables. This is surfaced by
adding an additional status field to the payload proto of jobs, and
concatenated to the running status when populating the interal jobs
table.

For dropping or truncating jobs, the detailed running status is
determined by the status of the table at the earliest stage of the
schema change.

Fixes #19004