fix: slow activation times (#174)

- Bundle using esbuild
- Up the ES version so that we compile less code
- turn the vscode ignore into an allowlist
- switch from dompurify to sanitize-html due to build issues

Author: Hellebore

.vscodeignore

@@ -1,10 +1,14 @@
-**/*.ts
-**/tsconfig.json
-.gitignore
-.idea/**
-.vscode/**
-.vscode-dev/**
-yarn.lock
-.git/**
-.pytest_cache/**
-assets/**
+
+*
+*/**
+**/.DS_Store
+!sourcery_binaries/**
+!out/**
+!package.json
+!sourcery-icon.png
+!welcome-to-sourcery.py
+!README.md
+!LICENSE
+!media/**
+!src/webview/**
+!walkthrough/**