Add metrics associated with the debugger that are reported through the
metrics writer. This adds a few attributes that are only added when a
debugger is used with either the `debug` command or `dap` command.
At the moment, these metrics show up the exact same as a build and we
can't identify if something is using `dap` or `debug` since they use the
same code path.
This also adds a new available metric that can be utilized by plugins to
report additional information. The metrics will check if an environment
variable `BUILDX_DAP_USER_AGENT` is sent and that will get included in
the metrics if they are enabled.
Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com>
Jonathan A. Sternberg
3e0e9333c2