Refactor/core qol adoption (#17655)

* Scripts: close every msg_info block with msg_ok

Past-tense msg_info calls that should have been msg_ok, notices that opened a block before a prompt, and blocks without a closing msg_ok. These already left a stale spinner; with core's block stack they would resume it after every later msg_ok.

* Generate passwords with random_password

openssl rand -base64 | tr -dc | head -c returned fewer characters than asked for, and the unfiltered | cut variants put / and + into passwords that end up in DSNs and sed expressions. Secrets an app decodes as base64 are unchanged. Requires community-scripts/core#61.

* Keep data directories through CLEAN_INSTALL instead of copying them

create_backup copied uploads, storage and similar directories twice per update and needed their size again in free space. CLEAN_INSTALL_KEEP moves them aside instead. Only directories the upstream release does not ship, in scripts that restored right after the fetch. Requires community-scripts/core#61.

* Drop the 300s uv timeout overrides

setup_uv exports UV_HTTP_TIMEOUT=600 now; the scripts' 300 only lowered it. Requires community-scripts/core#61.

install/openwebui-install.sh

@@ -46,7 +46,6 @@ if [[ ${prompt,,} =~ ^(y|yes)$ ]]; then
 fi
 
 msg_info "Installing Open WebUI"
-export UV_HTTP_TIMEOUT=300
 for attempt in $(seq 1 3); do
   $STD uv tool install --python 3.12 --constraint <(echo "numba>=0.60") "${OTEL_ARGS[@]}" open-webui[all] && break
   [[ $attempt -lt 3 ]] && msg_warn "Open WebUI install attempt $attempt failed, retrying..." && sleep 10