What

Changes the default preimages directory

Why

It creates unexpected behaviors and can potentially download preimages in a random directory ~/.octez-evm-node/_evm_installer_preimages.

Make the encodings and configuration helpers depends on the data_dir.

Document the interface of any function added or modified (see the coding guidelines)
Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
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