fix(logger): log file using pretty format not working

[felipecrs]

Changes

I tried to use LOG_FILE_FORMAT=pretty today and noticed it wasn't working at all. It was throwing an error at the very beginning of the execution:

> node lib/renovate.ts

 INFO: Renovate started
       "renovateVersion": "0.0.0-semantic-release"
ERROR: unhandledRejection
       "err": {
         "code": "ERR_INVALID_ARG_TYPE",
         "message": "The \"chunk\" argument must be of type string or an instance of Buffer, TypedArray, or DataView. Received an instance of Object",
         "stack": "TypeError: The \"chunk\" argument must be of type string or an instance of Buffer, TypedArray, or DataView. Received an instance of Object\n    at _write (node:internal/streams/writable:480:13)
         ...

This PR:

1. Fixes the error above
2. Fixes a TODO comment regarding typing of RenovateStream by rewriting it to Writable
3. Changes log file behavior when using pretty format to log without colors, since it otherwise makes the log file much harder to read
4. Implement a custom handle to format multi-line err.stack prettier for better readability (thanks @secustor)
5. Add tests.

Context

Please select one of the following:

• This closes an existing Issue, Closes: #
• This doesn't close an Issue, but I accept the risk that this PR may be closed if maintainers disagree with its opening or implementation

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