Remove top navbar menu

[yubiuser]

What does this PR aim to accomplish?:

Removes the top navbar menu.

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The menu does not offer a lot of information and was kind of "hidden".
The links to Github and pi-hole.net have been moved to the side bar, Donate was already there (and in the footer).
Now the session timer is missing, but the default session time is 24 hours minutes (see comments below) to there is no need to be constantly aware of the remaining time. And the link to the latest release has been removed, but it might be better to link to the discourse announcements instead of the core releases only anyway.

Additionally, I moved to logout button to the upper right corner of the top navbar. This is a location where usually logout buttons are placed.

Best to be merged after #2290

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[DL6ER]

but the default session time is 24 hours to there is no need to be constantly aware of the remaining time

This is interesting, this has initially been designed for 5 minutes. When staying on the dashboard, the API calls constantly bumped this time so you were never kicked out, but a session time of 24 hours seems pretty useless.

[rdwebdesign]

but the default session time is 24 hours to there is no need to be constantly aware of the remaining time

I think it is configured to 24 minutes.

If you access any page (except the dashboard), you will see the countdown. In the dashboard page the counter is constantly restarted and always shows 23 minutes and 59 seconds.

Anyway, this counter is useless.

[yubiuser]

Sorry, 24 minutes is right. It's php default.

https://www.php.net/manual/en/session.configuration.php#ini.session.gc-maxlifetime

It was always like this: https://github.com/pi-hole/AdminLTE/pull/197/files

[rdwebdesign]

My original suggestion was to turn this area into a useful menu, to reduce the main menu, like this:

Note:
I think the counter should be removed too.

[yubiuser]

If we keep the menu, we should use an other symbol to indicate that there is a menu. In my opinion the current symbol+logo or the proposed hostname do not indicate strong enough that a menu is hidden there.

[rdwebdesign]

I agree.

If we decide to keep the menu, we should use the "hamburger" menu icon

And use different icons for collapse/restore the menu:

[dschaper]

Please remove Designed for Raspberry Pi... They've come after us more than once for using their trademarked names.

[yubiuser]

I changed to hamburger menu icon to arrows which will change direction on click

[yubiuser]

Superseded by #2298