Update outdated references to the Cranelift repository

This patch updates or removes all references to the Cranelift repository. It affects links in README documents, issues that were transferred to the Wasmtime repository, CI badges, and a small bunch of sundry items.

cranelift/umbrella/Cargo.toml

@@ -5,7 +5,7 @@ version = "0.59.0"
 description = "Umbrella for commonly-used cranelift crates"
 license = "Apache-2.0 WITH LLVM-exception"
 documentation = "https://docs.rs/cranelift"
-repository = "https://github.com/bytecodealliance/cranelift"
+repository = "https://github.com/bytecodealliance/wasmtime"
 categories = ["no-std"]
 readme = "README.md"
 keywords = ["compile", "compiler", "jit"]
@@ -22,4 +22,3 @@ core = ["cranelift-codegen/core", "cranelift-frontend/core"]
 
 [badges]
 maintenance = { status = "experimental" }
-travis-ci = { repository = "bytecodealliance/cranelift" }