[opentelemetry-collector] Add extra ingress configurations

[clarkjohnd]

Overview

This PR adds a new values parameter extraIngresses to the OpenTelemetry Collector Helm chart. Use case for this is where multiple receivers are deployed in a single OpenTelemetry Collector configuration that need different ingress annotations/configuration. For example:

• Receiver A (OTLP receiver etc.) uses NGINX ingress controller but needs to whitelist IPs to client CIDR ranges (with annotations) to only allow metrics sent from external client environments
• Receiver B (AWS CloudWatch receiver etc.) uses NGINX ingress controller but needs to whitelist AWS CIDR ranges (with annotations) to only allow metrics sent from AWS platform through CloudWatch Metric Streams

This can currently be acomplished by manually deploying another ingress resource or by deploying another Helm installation, but this change allows it to be done in a single installation instead.

Changes

extraIngresses merges with ingress configuration in the Ingress resource template and builds from a range function, so a few minor changes in code but no changes to end result if no extraIngresses defined. Reason for doing it this way is to avoid breaking changes by changing ingress to a map list etc. extraIngresses default values is [], so no impact on existing installations with chart version updates.

The schema for extraIngresses elements is the same as ingress with the following exceptions:

• No enabled key - this is inherited from ingress configuration
• A name key (required) exists to differentiate ingress resources - this is used as a suffix for the ingress resource to differentiate from the root ingress (no suffix) and other additional ingress resources.

A new CI values file has been added (and tested), and chart version minor updated to v0.26.0. Open to any feedback or suggested changes!

[linux-foundation-easycla[bot]]

The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: clarkjohnd / name: John Clark (0d7d316414e52e13621de051a1c4ef7eeaeee0e0, b76a263820e97f4f5a8cb68a7baaa7686f2691d2, 5364a486f024edee86228c8e9578862a8ac1881c, 246601bc35cf9676cba8cc819cd135db7154c27f, f4e520938f980e51a20a94f0744e3504e5e7453b, 59bd3590ec3ab2a22635f43cdbfcfa274b00d675, 6153ab7910f2c2385f02f0795e99c02fea3c45e5)