Addded support for config_merger filtering of root properties

[azun]

Description

Allows filtering the output config properties from himl-config-merger. Filter rules are part of the configs and can be defined hierarchically. The rules sit under a key that is passed as an argument to the tool through --filter-rules-key

Related Issue

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Motivation and Context

Output configs can become very big when values are being reused/interpolated between levels or on the same level. For example a property defined at the root level is only needed by a subset of clusters. To minimize the output, the only partial solution currently is to overwrite that property for all the leaf paths that don't need it. When configuring multiple clusters/services, default properties get populated and are never used.

How Has This Been Tested?

Added a hierarchy with filters in the examples folder with values convering multiple scanarios:

• rule selectors for multiple keys with explicit value or matching a pattern
• rules keeping a list of properties
• rules keeping properties that match a pattern

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[alex-necula]

👍🏻🛳️🇮🇹

[danielcoman]

👍🏻