feat/flask: images cleanup

- delete obsolete images
- resort images by folders
- add proper alt= parameters and standartized closing to <img> tags

static/img/telegram.svg

@@ -1 +0,0 @@
-<svg viewBox="0 0 16 16" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><linearGradient id="a" x1="66.67%" x2="41.67%" y1="16.67%" y2="75%"><stop offset="0" stop-color="#37aee2"/><stop offset="1" stop-color="#1e96c8"/></linearGradient><linearGradient id="b" x1="65.97%" x2="85.12%" y1="43.69%" y2="80.24%"><stop offset="0" stop-color="#eff7fc"/><stop offset="1" stop-color="#fff"/></linearGradient><circle cx="8" cy="8" fill="url(#a)" r="8"/><path d="m6.53333333 11.6666667c-.25917333 0-.21513333-.09786-.30452-.3446334l-.76214666-2.50830663 5.86666663-3.48039334" fill="#c8daea"/><path d="m6.53333333 11.6666667c.2 0 .28836667-.0914667.4-.2l1.06666667-1.0372-1.33053333-.80233337" fill="#a9c9dd"/><path d="m6.66933333 9.62733333 3.224 2.38193337c.36789997.2029933.63342667.0978933.72506667-.3415667l1.3123333-6.1842c.13436-.53868-.20534-.783-.5572933-.62321333l-7.706 2.9714c-.52600667.21098-.52294.50444-.09588.6352l1.97753333.61722 4.57819997-2.88833334c.2161267-.13106.4144867-.06059933.25168.08389334" fill="url(#b)"/></svg>