Lead back to main documentation from doxygen

[toonst]

Is your enhancement proposal related to a problem? Please describe.

When I'm browsing the Zephyr documentation and I go to doxygen by clicking on "API", there is no way to get back to the main documentation.

Describe the solution you'd like
When I'm browsing the Zephyr documentation, clicking on "API" to get to the doxygen documentation, I would like to be able to get back to the main documentation by clicking the Zephyr logo.

Describe alternatives you've considered
A clickable link "Back to main documentation" in the left pane on doxygen might be good also.

Additional context

[kartben]

+1, thanks for filing the issue as this has been on my mental list for a while :)

Edit: not sure I agree that clicking on the zephyr logo is where this should be happening though