QoL: Search bar in Add uniform/texture

[Martysh12]

Problem

Reading a large list of uniforms one-by-one is tedious.

Solution

Add a search bar to search for uniforms easily.

[markusfisch]

Good idea! Will add this as soon as I find enough time.

[Martysh12]

@markusfisch, I opened a Pull Request that should fix this issue, please take a look!