Improve search system

[mbkma]

shell: Add EvFindSidebar widget to show search results
see https://gitlab.gnome.org/GNOME/evince/-/commit/940ce8048e4fc6503dca03c1ce090ff4a11dface

eggfindbar: don't close the findbar when it loses the focus
see https://gitlab.gnome.org/GNOME/evince/-/commit/a2d781fb124bd19861035fd41dacc976e00d19ef

shell: Add the findbar to the main box instead of the view box

libview: Add ev_view_find_set_result

Fixes #238

[raveit65]

I tried to back port the same functionality 2 years ago or so. So i like this.
But i recall that there was a lot of more commits which are related to the new search sidebar, but i am not sure.

[raveit65]

Beside from a few code-style issues it works fine, thanks.

[mbkma]

This does not work with epub documents yet...

[raveit65]

@mbkma
Any chance to fix code-style issues?

[raveit65]

Opps, cross posting :)

[lukefromdc]

This works, though use is a bit counterintuative. The search sidebar is brought up by and only by clicking on the search icon in toolbar, which brings up the previous search gui plus a sidebar listing all findings of the word searched for (tested using a word). This comes up automatically, overriding other sidebars such as thumbnails. I had expected to be able to select it from the sidebar mode combo box.

None the less, this works