* Revert "History, more test coverage improvements, and refactorings. (#3217)"
This reverts commit 8fc8fc89aaf0ab40e7a149f2286eb97515f4ac9b.
* Add tests
* Refactor .nu-env
* Change logic of Config write to logic of read()
* Fix reload always appends to old vars
* Fix reload always takes last_modified of global config
* Add reload_config in evaluation context
* Reload config after writing to it in cfg set / cfg set_into
* Add --no-history to cli options
* Use --no-history in tests
* Add comment about maybe_print_errors
* Get ctrl_exit var from context.global_config
* Use context.global_config in command "config"
* Add Readme in engine how env vars are now handled
* Update docs from autoenv command
* Move history_path from engine to nu_data
* Move load history out of if
* No let before return
* Add import for indexmap
Improvements overall to Nu. Also among the changes here, we can also be more confident towards incorporating `3041`. End to end tests for checking envs properly exported to externals is not added here (since it's in the other PR)
A few things added in this PR (probably forgetting some too)
* no writes happen to history during test runs.
* environment syncing end to end coverage added.
* clean up / refactorings few areas.
* testing API for finer control (can write tests passing more than one pipeline)
* can pass environment variables in tests that nu will inherit when running.
* No longer needed.
* no longer under a module. No need to use super.
* move basic_shell_manager to nu-engine
* move basic_evaluation_context to nu-engine
* fix failing test in feature which commands/classified/external.rs
