Extract TOML support into an extension (#9940)

This PR extracts TOML support into an extension and removes the built-in
TOML support from Zed.

There's a small workaround necessary in order for us to set the file
permissions on the `taplo` binary so that it can be run. Eventually
we'll want to build this into the extension API, but for now we're just
hard-coding it on the host side.

Release Notes:

- Removed built-in support for TOML, in favor of making it available as
an extension. The TOML extension will be suggested for download when you
open a `.toml` or `Cargo.lock` file.

extensions/toml/extension.toml

@@ -0,0 +1,18 @@
+id = "toml"
+name = "TOML"
+description = "TOML support."
+version = "0.0.2"
+schema_version = 1
+authors = [
+    "Max Brunsfeld <max@zed.dev>",
+    "Ammar Arif <evergreenkary@gmail.com>"
+]
+repository = "https://github.com/zed-industries/zed"
+
+[language_servers.taplo]
+name = "Taplo"
+language = "TOML"
+
+[grammars.toml]
+repository = "https://github.com/tree-sitter/tree-sitter-toml"
+commit = "342d9be207c2dba869b9967124c679b5e6fd0ebe"