fix(config): env variable bug

[ocervell]

When overriding SECATOR_DIRS_DATA using env variable, the other paths calculated from it are not re-calculated, se for instance templates SECATOR_DIRS_TEMPLATE still go to ~/.secator/templates. It's kind of anoying chicken-and-eggs bug ....

Three options:

• Switch to generated paths for all folders below data/, which means we won't be able to configure individual paths under data anymore

or

• (longer) switch current implementation to https://docs.pydantic.dev/latest/concepts/pydantic_settings/#environment-variable-names4

or

• (anoying) fix current bug, meaning we should:
  • override default config with env variables
  • ?