Add slides for the Proxy-Wasm presentation (2021-04-22). (#429)

Signed-off-by: Piotr Sikora <[email protected]>

Author: PiotrSikora

meetings/2021/WASI-04-22.md

@@ -28,7 +28,7 @@ The meeting will be on a zoom.us video conference.
 1. Announcements
     1. _Sumbit a PR to add your announcement here_
 1. Proposals and discussions
-    1. [Proxy-Wasm](https://github.com/proxy-wasm) update (Piotr Sikora, [slides](https://docs.google.com/presentation/d/1PYuWke-XDJhAYdCUIw20_I-LoR2IVfJlo5Gn784fFYs/edit?usp=sharing&resourcekey=0-vnuIEdhe_kdc9VHQ6-o2Pg))
+    1. [Proxy-Wasm](https://github.com/proxy-wasm) update (Piotr Sikora, [slides](presentations/2021-04-22-PiotrSikora-Proxy-Wasm.pdf))
     1. _Sumbit a PR to add your agenda item here_
 
 ## Notes
@@ -49,8 +49,6 @@ The meeting will be on a zoom.us video conference.
 
 **Piotr Sikora:** Update on proxy-wasm. People have changed, so going to recap.
 
-Slides: https://docs.google.com/presentation/d/1PYuWke-XDJhAYdCUIw20_I-LoR2IVfJlo5Gn784fFYs/edit?usp=sharing&resourcekey=0-vnuIEdhe_kdc9VHQ6-o2Pg
-
 Primary reason is to extend capabilities of proxies with business logic. Ideally running on different proxies and providers. Run in Nginx, istio, fastly, and works exactly the same on the platforms. Started as part of istio to allow code at runtime with security, but that’s not the only reason. Primary reason is abstraction across different providers.
 
 Have support for logging, metrics, network filters, HTTP and gPRC callouts, can do auth check, have key-value store (non-durable, only used to coordinate e.g. telemetry, not meant as DB), background services and timers, FFI.