[6.x] Use custom logo in the header the same way as statamic logo (and not as a replacement of the logo text)

[helloDanuk]

I like how the Statamic logo and logo text is used together in the header.

It would be great to use a custom logo the same way. Together with the custom_logo_text it would look like this:

• The custom_logo_text would not be a replacement for the custom_logo anymore.
• It would be possible to add a small favicon-style-logo together with the optional custom_logo_text.
• If you have a wider logo with text, you could simply leave custom_logo_text empty.

Current behaviour is this:

• you can either give it a custom_logo_text (with statamic logo enabled)
• or switch to a custom logo, without custom_logo_text