[GEN-1959]: add IBM Instana destination

[BenElferink]

This pull request introduces support for IBM Instana as a new destination in the configuration. The changes include adding configuration options, updating documentation, and integrating Instana into the existing system.

Key changes include:

Instana Configuration

• Added Instana struct and associated methods in common/config/instana.go to handle Instana-specific configuration.
• Introduced InstanaDestinationType in common/dests.go to identify Instana as a destination type.

Utility Functions

• Added errorMissingKey function in common/config/utils.go to handle missing configuration keys.

Documentation Updates

• Added documentation for configuring IBM Instana in docs/backends/instana.mdx.
• Updated docs/adding-new-dest.mdx to reflect the new error handling and pipeline names. [1] [2] [3]
• Included IBM Instana in the backends overview in docs/backends-overview.mdx.
• Updated docs/mint.json to include the new Instana backend documentation.

YAML Configuration

• Added destinations/data/instana.yaml to define the Instana destination fields and properties.

[blumamir]

LGTM 💯