Initial addition of CODEOWNERS file (#4620)

* Initial addition of CODEOWNERS file

* Proposed sub-team ownership (#4632)

* Updating for the events module to be both language and execution

* Adding more comment details

Co-authored-by: Jeremy Cohen <jeremy@dbtlabs.com>

.github/CODEOWNERS

@@ -0,0 +1,43 @@
+# This file contains the code owners for the dbt-core repo.
+# PRs will be automatically assigned for review to the associated 
+# team(s) or person(s) that touches any files that are mapped to them.
+#
+# A statement takes precedence over the statements above it so more general
+# assignments are found at the top with specific assignments being lower in
+# the ordering (i.e. catch all assignment should be the first item)
+#
+# Consult GitHub documentation for formatting guidelines:
+# https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners#example-of-a-codeowners-file
+
+# As a default for areas with no assignment, 
+# the core team as a whole will be assigned
+*       @dbt-labs/core
+
+# Changes to GitHub configurations including Actions
+/.github/ @leahwicz
+
+# Language core modules
+/core/dbt/config/     @dbt-labs/core-language
+/core/dbt/context/    @dbt-labs/core-language
+/core/dbt/contracts/  @dbt-labs/core-language
+/core/dbt/deps/       @dbt-labs/core-language
+/core/dbt/parser/     @dbt-labs/core-language
+
+# Execution core modules
+/core/dbt/events/     @dbt-labs/core-execution @dbt-labs/core-language # eventually remove language but they have knowledge here now
+/core/dbt/graph/      @dbt-labs/core-execution
+/core/dbt/task/       @dbt-labs/core-execution
+
+# Adapter interface, scaffold, Postgres plugin
+/core/dbt/adapters    @dbt-labs/core-adapters
+/core/scripts/create_adapter_plugin.py    @dbt-labs/core-adapters
+/plugins/             @dbt-labs/core-adapters
+
+# Global project: default macros, including generic tests + materializations
+/core/dbt/include/global_project    @dbt-labs/core-execution @dbt-labs/core-adapters
+
+# Perf regression testing framework
+# This excludes the test project files itself since those aren't specific 
+# framework changes (excluded by not setting an owner next to it- no owner)
+/performance @nathaniel-may
+/performance/projects