[Behavior Flags] Add project flags to Project to be passed into BaseAdapter

[mikealfare]

Housekeeping

• I am a maintainer of dbt-core

Short description

BaseAdapter needs access to project flags so that users are able to override default settings on behavior flags. BaseAdapter cannot get this information from project files; all config gets passed in during instantiation. The current behavior is to explicitly parse these flags in dbt-core. However, this behavior prevents adapter maintainers from creating their own behavior flags, and increases the complexity for first party adapters to create behavior flags.

Acceptance criteria

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1. The RuntimeConfig object that gets passed into the BaseAdapter factory method includes all project flags
2. Existing interfaces are not broken; this is an additive change
3. All protocols are updated to reflect this change (some are in dbt-adapters, e.g. AdapterRequiredConfig, and will be handled in a separate ticket)
4. The new flags attribute does not consider CLI arguments nor environment variables, only what is contained in dbt_project.yml

Suggested Tests

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1. Create a RuntimeConfig instance, show that there's an empty dictionary for .flags
2. Create a behavior flag and override it in project_config_update, verify the value on RuntimeConfig
3. Create a behavior flag and attempt to override it via CLI args, verify it's not overridden on RuntimeConfig
4. Create a behavior flag and attempt to override it via environment variables, verify it's not overridden on RuntimeConfig

Impact to Other Teams

This impacts Adapters, but is also being executed by Adapters.

Will backports be required?

N/A

[FishtownBuildBot]

Opened a new issue in dbt-labs/docs.getdbt.com: dbt-labs/docs.getdbt.com#6031