Injecting Region Mapping Config into KEB

[ralikio]

Description

Passing region mapping to KEB based on mounted config map as it was done in eu whitelist functionality.

Changes proposed in this pull request:

• default template values in values.yaml,
• mounting config as container's file through mounted config map volume.
• config path passed as env variable to KEB envconfig.

Related issue(s)

#793

[kyma-bot]

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[github-actions]

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