[android] make toolbar fixed at the top of the screen

[lazymonkey2]

Describe the feature you'd like to request

I'm using version 5.2.6 of android app.
I've a folder with many bookmarks, and I have seen that scrolling down make not visible the app toolbar at the top.
The toolbar with the buttons should remain always visible, and I should be able to scroll only the bookmarks.
Same think applies to app messages, that also can be scrolled up and made not visible.

Describe the solution you'd like

the app toolbar should be fixed at the top of the screen, and neve scroll away.
same for app messages (for example errors).

Describe alternatives you've considered

N/A

[github-actions]

Hello 👋

Thank you for taking the time to open this issue with floccus. I know it's frustrating when software
causes problems. You have made the right choice to come here and open an issue to make sure your problem gets looked at
and if possible solved.
I'm Marcel and I created floccus a few years ago, maintaining it ever since. I currently work for Nextcloud
which leaves me with less time for side projects like this one than I used to have.
I still try to answer all issues and if possible fix all bugs here, but it sometimes takes a while until I get to it.
Until then, please be patient.
Note also that GitHub is a place where people meet to make software better together. Nobody here is under any obligation
to help you, solve your problems or deliver on any expectations or demands you may have, but if enough people come together we can
collaborate to make this software better. For everyone.
Thus, if you can, you could also have a look at other issues to see whether you can help other people with your knowledge
and experience. If you have coding experience it would also be awesome if you could step up to dive into the code and
try to fix the odd bug yourself. Everyone will be thankful for extra helping hands!
To continue the development and maintenance of this project in a sustainable way it is expected that you donate to the project when opening a ticket,
if you're not a donor already. You can find donation options at https://floccus.org/donate/. Thank you!

One last word: If you feel, at any point, like you need to vent, this is not the place for it; you can go to the Nextcloud forum,
to twitter or somewhere else. But this is a technical issue tracker, so please make sure to
focus on the tech and keep your opinions to yourself.

I look forward to working with you on this issue
Cheers 💙

[marcelklehr]

I agree. A more static appearance would be good. Thank you for the feedback!