[feature/server-side-search] Add server-side search support

[felix-schwarz]

Description

This PR adds server-side search support to the app.

TODO

• add search scope backed by OCSearchResult
• improve error and result handling in OCSearchResult
• add KQL syntax generator to OCQueryCondition (similar to the SQL syntax generator)

Related Issue

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)

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