Move crates/api to crates/wasmtime (#1693)

The `wasmtime` crate currently lives in `crates/api` for historical
reasons, because we once called it `wasmtime-api` crate. This creates a
stumbling block for new contributors.

As discussed on Zulip, rename the directory to `crates/wasmtime`.

crates/wasmtime/Cargo.toml

@@ -0,0 +1,49 @@
+[package]
+name = "wasmtime"
+version = "0.16.0"
+authors = ["The Wasmtime Project Developers"]
+description = "High-level API to expose the Wasmtime runtime"
+documentation = "https://docs.rs/wasmtime"
+license = "Apache-2.0 WITH LLVM-exception"
+repository = "https://github.com/bytecodealliance/wasmtime"
+readme = "README.md"
+edition = "2018"
+
+[dependencies]
+wasmtime-runtime = { path = "../runtime", version = "0.16.0" }
+wasmtime-environ = { path = "../environ", version = "0.16.0" }
+wasmtime-jit = { path = "../jit", version = "0.16.0" }
+wasmtime-profiling = { path = "../profiling", version = "0.16.0" }
+wasmparser = "0.52.0"
+target-lexicon = { version = "0.10.0", default-features = false }
+anyhow = "1.0.19"
+region = "2.0.0"
+libc = "0.2"
+cfg-if = "0.1.9"
+backtrace = "0.3.42"
+rustc-demangle = "0.1.16"
+lazy_static = "1.4"
+wat = { version = "1.0.10", optional = true }
+
+[target.'cfg(target_os = "windows")'.dependencies]
+winapi = "0.3.7"
+
+[dev-dependencies]
+tempfile = "3.0"
+
+[badges]
+maintenance = { status = "actively-developed" }
+
+[features]
+default = ['wat', 'jitdump']
+
+# Enables experimental support for the lightbeam codegen backend, an alternative
+# to cranelift. Requires Nightly Rust currently, and this is not enabled by
+# default.
+lightbeam = ["wasmtime-jit/lightbeam"]
+
+# Enables support for the `perf` jitdump profiler
+jitdump = ["wasmtime-jit/jitdump"]
+
+# Enables support for the `VTune` profiler
+vtune = ["wasmtime-jit/vtune"]