feat(ci): expand testcontainers coverage to mariadb, timescaledb, yugabytedb, monetdb, mongodb

Adds five more dialects to the testcontainers suite, stacked on top of the
7-dialect pilot in feat/testcontainers-nightly-pilot: mariadb, timescaledb,
yugabytedb, monetdb, mongodb.

mariadb, timescaledb, and yugabytedb are all wire-compatible with an
existing base dialect (MySQL and Postgres respectively), so they reuse
testcontainers' MySqlContainer/PostgresContainer classes pointed at a
different image rather than needing new container-class wiring.
yugabytedb specifically cannot reuse PostgresContainer's built-in
readiness check, though: that execs `psql`, which the yugabyte image
doesn't ship (only its own `ysqlsh`) -- uses a generic DockerContainer
instead, started via `yugabyted start` and waiting on its own final
startup log line.

monetdb has no native testcontainers module; uses a generic DockerContainer
with the documented MDB_* environment variables. Publishes an amd64-only
image (confirmed running under Rosetta/QEMU emulation on Apple Silicon,
unlike CrateDB's harder x86-64-v3 CPU requirement).

mongodb needed a different data-setup approach, like elasticsearch before
it: documents get inserted via the native pymongo driver, not SQL INSERT,
since MongoDB is schemaless and Superset talks to it through pymongosql
(a SQL-to-MongoDB translation layer requiring a `?mode=superset` query
param). Two real bugs surfaced writing this one: testcontainers'
MongoDbContainer.get_connection_url() has no database path or query
string at all, so naively appending "&mode=superset" glued directly onto
the port number instead of starting a query string; and the root user
MongoDbContainer creates lives in the `admin` database, so connecting
with a different default database in the URL requires authSource=admin
or authentication fails outright. Confirmed pymongosql supports OFFSET
(maps to MongoDB's native `skip`), unlike Elasticsearch's SQL layer.

mariadb could not be verified locally in this environment: mysqlclient
(MySQLdb) has a pre-existing, unrelated native-library linking issue
against this machine's Homebrew-installed libmysqlclient. CI installs it
via apt on Linux, where this does not occur -- same accepted pattern
already used for crate/mssql/db2 in the base branch.

.github/workflows/testcontainers.yml

@@ -58,6 +58,16 @@ jobs:
             timeout: 15
           - dialect: db2
             timeout: 25
+          - dialect: mariadb
+            timeout: 10
+          - dialect: timescaledb
+            timeout: 10
+          - dialect: yugabytedb
+            timeout: 10
+          - dialect: monetdb
+            timeout: 10
+          - dialect: mongodb
+            timeout: 10
     timeout-minutes: ${{ matrix.timeout }}
     env:
       PYTHONPATH: ${{ github.workspace }}