Add `exasol_info` for server and cluster facts

[skyglass]

Labels: module, exasol_info, mvp

Use case ID: UC-EXASOL-INFO

Gherkin feature: Feature: exasol_info - gather server info

Primary actor: Exasol DBA

Goal: gather Exasol server information without writing custom Python scripts.

Trigger: a playbook task calls exasol_info.

Preconditions:

• The Exasol cluster is reachable from the Ansible controller.
• The user can query the metadata needed for version and cluster information.

Main flow:

1. The user calls exasol_info with valid login_* parameters.
2. The module opens a pyexasol connection.
3. The module queries server version, database name, and cluster size.
4. The module returns facts and changed: false.

Acceptance criteria:

• Result contains version.
• version matches a semver-like Exasol version string where available.
• Result contains cluster_size.
• Against single-node Exasol One, cluster_size equals 1.
• The module always returns changed: false.
• The module supports check mode.
• Integration tests run against Exasol One.

Implementation notes:

• This module is direct replacement for the recurring version-check
  Python job.
• Prefer simple metadata queries over broad fact collection in v1.