build: add useful scripts for installing template

Can now install it locally (or anywhere else) quite easily. This is the first step for being able to auto create PRs when we do a release

scripts/uninstall

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+set -eu
+
+# adapted from https://github.com/johannes-wolf/cetz/blob/35c0868378cea5ad323cc0d9c2f76de8ed9ba5bd/scripts/package
+# licensed under Apache License 2.0
+
+. "$(dirname "${BASH_SOURCE[0]}")/setup"
+
+if (( $# < 1 )) || [[ "${1:-}" == "help" ]]; then
+  echo "uninstall TARGET"
+  echo ""
+  echo "Removes the package installed into a directory named '<name>/<version>'"
+  echo "at TARGET. If TARGET is set to @local or @preview, the local Typst package"
+  echo "directory will be used so that the package gets installed for local use."
+  echo "The name and version are read from 'typst.toml' in the project root."
+  echo ""
+  echo "Local package prefix: $DATA_DIR/typst/package/local"
+  echo "Local preview package prefix: $DATA_DIR/typst/package/preview"
+  exit 1
+fi
+
+TARGET="$(resolve-target "${1:?Missing target path, @local or @preview}")"
+echo "Install dir: $TARGET"
+
+TARGET="${TARGET:?}/${PKG_PREFIX:?}/${VERSION:?}"
+echo "Package to uninstall: $TARGET"
+if [[ ! -e "${TARGET:?}" ]]; then
+  echo "Package was not found."
+elif rm -r "${TARGET:?}" 2>/dev/null; then
+  echo "Successfully removed."
+else
+  echo "Removal failed."
+fi