This commit adds a set of commands to monitor for enabling breakpoint debugger.
This is implemented based on the walker utility for step-by-step LLB inspection.
For each vertex and breakpoint, monitor calls Solve API so the user can enter to
the debugger container on each vertex for inspection.
User can enter to the breakpoint debugger mode by --invoke=debug-step flag.
Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
This commit moves monitor commands to `monior/commands` package.
Commands still need access to the `monitor` object and buildx controller so this
commit enables this via `Monitor` interface stored in `monitor/types`.
Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
