Add format_error_message function

[drew2a]

This PR addresses #6810

This PR changes the error formatting style in "on_core_finished with an error".

Two changes:

1. Added translation from err_code to strerror
2. Added quoting for the last core output

An example of an error message:

The Tribler core has unexpectedly finished with exit code 2 and status: 2.

Error message: No such file or directory

Last core output:
> ERROR <loggingstuff:8> root.print_error(): Something went wrong!
> Traceback (most recent call last):,
>   File "ipv8  askmanager.py", line 131, in done_cb,
>   File "ipv8\messagingnonymization\hidden_services.py", line 366, in on_create_e2e,
>   File "ipv8\messagingnonymization\hidden_services.py", line 378, in create_created_e2e,
> KeyError: 1030643827

Ref:

• https://docs.python.org/3/library/errno.html
• https://docs.python.org/3/library/os.html#os.strerror