ui/compress: Do not change git worktree (#10467)

This change makes sure that the git worktree is not changed while
compressing assets, making it better for local development.

To achieve this, the compression script keeps the un-compressed assets
and generates the go:embed directory when compressing the files.

A .gitignore file has been added to ignore generated files.

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

scripts/compress_assets.sh

@@ -1,5 +1,11 @@
 #!/usr/bin/env bash
 #
-# [de]compress static assets
+# compress static assets
 
-find web/ui/static -type f -exec gzip "$@" {} \;
+set -euo pipefail
+
+cd web/ui
+cp embed.go.tmpl embed.go
+find static -type f -name '*.gz' -delete
+find static -type f -exec gzip -fk '{}' \; -print0 | xargs -0 -I % echo %.gz | xargs echo //go:embed >> embed.go
+echo var EmbedFS embed.FS >> embed.go