debugger: Use DAP schema to configure daps (#30833)

This PR allows DAPs to define their own schema so users can see
completion items when editing their debug.json files.

Users facing this aren’t the biggest chance, but behind the scenes, this
affected a lot of code because we manually translated common fields from
Zed's config format to be adapter-specific. Now we store the raw JSON
from a user's configuration file and just send that.

I'm ignoring the Protobuf CICD error because the DebugTaskDefinition
message is not yet user facing and we need to deprecate some fields in
it.

Release Notes:

- debugger beta: Show completion items when editing debug.json
- debugger beta: Breaking change, debug.json schema now relays on what
DAP you have selected instead of always having the same based values.

---------

Co-authored-by: Remco Smits <djsmits12@gmail.com>
Co-authored-by: Cole Miller <m@cole-miller.net>
Co-authored-by: Cole Miller <cole@zed.dev>

.zed/debug.json

@@ -2,13 +2,13 @@
   {
     "label": "Debug Zed (CodeLLDB)",
     "adapter": "CodeLLDB",
-    "program": "target/debug/zed",
+    "program": "$ZED_WORKTREE_ROOT/target/debug/zed",
     "request": "launch"
   },
   {
     "label": "Debug Zed (GDB)",
     "adapter": "GDB",
-    "program": "target/debug/zed",
+    "program": "$ZED_WORKTREE_ROOT/target/debug/zed",
     "request": "launch",
     "initialize_args": {
       "stopAtBeginningOfMainSubprogram": true