refactor(web/converse): Use crimp instead of reqwest

This simpler, curl-based HTTP client (which I wrote years ago) is a
first step towards cleaning up the dependency mess of converse.

Dependency stats: +4, -28

Change-Id: I4f5f3c9307895d261bfb0a6bcf2337b747f9a4c0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2859
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

web/converse/Cargo.toml

@@ -10,6 +10,7 @@ actix-web = "0.7"
 askama = "0.6"
 chrono = { version = "0.4", features = ["serde"] }
 comrak = "0.2"
+crimp = "0.2"
 diesel = { version = "1.2", features = ["postgres", "chrono", "r2d2"]}
 env_logger = "0.5"
 failure = "0.1"
@@ -21,7 +22,6 @@ mime_guess = "2.0.0-alpha"
 pq-sys = "=0.4.4"
 r2d2 = "0.8"
 rand = "0.4"
-reqwest = "0.9"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
@@ -29,6 +29,7 @@ tokio = "0.1"
 tokio-timer = "0.2"
 url = "1.7"
 url_serde = "0.2"
+curl = "*" # bounded by crimp
 
 [build-dependencies]
 pulldown-cmark = "0.1"