[feature:gsoc26] Add Docker support for InfluxDB 2.0 and Elasticsearch backends

[pushpitkamboj]

Currently docker-openwisp only ships with InfluxDB 1.8. This issue tracks adding Docker Compose entries and environment variable mappings for both InfluxDB 2.0 and Elasticsearch.

Scope

• Add Docker Compose service support for InfluxDB 2.0.
• Add Docker Compose service support for Elasticsearch.
• Add environment variable mappings required by OpenWISP Monitoring for the new backends.
• Allow operators to switch among InfluxDB 1.8, InfluxDB 2.0, and Elasticsearch via a documented environment variable or set of variables.
• Provide sane defaults for local development and basic deployments.
• Allow advanced configuration through environment variables.
• Include persistent volumes for the new services where appropriate.
• Document any upgrade or migration notes needed when introducing the new services.

InfluxDB 2.0 environment mappings to cover

• URL or host/port configuration.
• Organization.
• Token.
• Bucket name.
• Retention configuration if exposed.

Elasticsearch environment mappings to cover

• Hosts.
• Scheme.
• Authentication or API key options.
• Index name.
• Index Lifecycle Management policy options if exposed.
• Shard and replica settings if exposed.
• Resource settings if needed for reliable local development.

Acceptance criteria

• Docker-based deployments can run with InfluxDB 2.0 without manual installation steps.
• Docker-based deployments can run with Elasticsearch without manual installation steps.
• Operators can switch among InfluxDB 1.8, InfluxDB 2.0, and Elasticsearch through documented environment variables.
• Default values are sufficient for a basic working setup.
• Advanced values can be overridden without editing application code.

[nemesifier]

I updated the issue body to make the Docker deployment scope and acceptance criteria more explicit.

The changes add service, environment variable, persistence, switching, sane default, and advanced configuration expectations for the new timeseries backends.

To review the body changes, navigate to the top bar of the issue body, click last edited by nemesifier, then click most recent to review the edit history. Unfortunately there is no quick URL I can share for this view.