This adds the following:
* A `compile_commands` target for the ninja_build.sh script.
This generates a `compile_commands.json` file, which is used
by tools such as clangd, in a new target directory called
`build.tooldata`. Unity builds must be disabled for the database
to be complete; see [this Discord comment by Casper Jeukendrup](https://discord.com/channels/818804595450445834/939880479887327302/1001483416753143818)
for more info.
* Additionally, a configuration file for clangd has been created
to tell it to find the file in the `build.tooldata` directory.
* Add a one-line change to the workspace settings for VSCode,
telling it where to find the Uncrustify config.
+merlan #flirora