ui: add asset image on create channel view; allow to choose image on create profile (#6891)

* ui: create channel picture

* more centered

* better symmetry

* less diff

* choose image on create profile

* fix padding

* fix padding, fit into screen

* fix button layout

* placeholders

* fix padding

* channel pictures

* adjust asset_dir in scripts

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Co-authored-by: Evgeny Poberezkin <evgeny@poberezkin.com>
Co-authored-by: shum <github.shum@liber.li>

apps/multiplatform/common/src/commonMain/resources/assets/default/MR/images/create_channel.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
+  <path d="M0,0h24v24H0z" fill="#00000000"/>
+</svg>

apps/multiplatform/common/src/commonMain/resources/assets/default/MR/images/create_channel_light.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
+  <path d="M0,0h24v24H0z" fill="#00000000"/>
+</svg>