Adblock Support for Embeds (#308)

Fixes #307 

- Adds optional adblock support, via wabac.js (dependent on
webrecorder/wabac.js#167).
- For now, adblock enabled only for embeds via the `useAdblock`
attribute, and can be enabled per archived item.
- By default, adblock filter rules from
[EasyList](https://easylist.to/easylist/easylist.txt) are used, however,
a custom filter rules file can be used via `adblockRulesUrl` attribute
(default is ./adblock/adblock.gz)
- Added `fetch-adblock.sh` script to fetch latest easylist, filter out
`##` rules and compress to `./adblock/adblock.gz`
- Not yet possible to enable adblock for standalone browsing via
replayweb.page
- bumps version to 2.0.0-beta.3

src/embed.ts

@@ -29,6 +29,8 @@ let defaultReplayFile = "";
 
 const DEFAULT_REPLAY_BASE = "https://replayweb.page/";
 
+const DEFAULT_ADBLOCK_FILE = "./adblock/adblock.gz";
+
 // ===========================================================================
 class Embed extends LitElement {
   @property({ type: String }) url = "";
@@ -64,6 +66,9 @@ class Embed extends LitElement {
   @property({ type: Boolean }) noCache = false;
   @property({ type: Boolean }) hideOffscreen: boolean | undefined;
 
+  @property({ type: Boolean }) useAdblock = false;
+  @property({ type: String }) adblockRulesUrl = DEFAULT_ADBLOCK_FILE;
+
   @property({ type: String }) newWindowBase = "";
 
   @property({ type: String }) errorMessage:
@@ -287,6 +292,7 @@ class Embed extends LitElement {
         loading?: "eager";
         swName?: string;
         ruffle?: "1";
+        adblockUrl?: string;
       } = {
         source,
         customColl: this.coll,
@@ -324,6 +330,10 @@ class Embed extends LitElement {
         params.ruffle = "1";
       }
 
+      if (this.useAdblock && this.adblockRulesUrl) {
+        params.adblockUrl = this.adblockRulesUrl;
+      }
+
       this.paramString = new URLSearchParams(
         // Converting to unknown here so that we can ignore the URL -> string conversion necessary for the types to work out
         params as unknown as Record<string, string>,