targets: add "adb" flash method using Android Debug Bridge

Add a new flash method that uses adb to flash boards over Android Debug
Bridge. The method supports running pre-flash shell commands via
"adb shell", pushing the firmware binary via "adb push", and running
post-flash shell commands with a {remote} token for the remote path.

New target JSON fields:
- adb-pre-commands: shell commands to run before pushing firmware
- adb-push-remote: remote device path for adb push
- adb-post-commands: shell commands to run after pushing firmware

Switch arduino-uno-q target to use the new adb flash method with
openocd running on the remote device.

Signed-off-by: deadprogram <ron@hybridgroup.com>

compileopts/config.go

@@ -536,7 +536,7 @@ func (c *Config) Programmer() (method, openocdInterface string) {
 	case "":
 		// No configuration supplied.
 		return c.Target.FlashMethod, c.Target.OpenOCDInterface
-	case "openocd", "msd", "command":
+	case "openocd", "msd", "command", "adb":
 		// The -programmer flag only specifies the flash method.
 		return c.Options.Programmer, c.Target.OpenOCDInterface
 	case "bmp":

compileopts/target.go

@@ -64,6 +64,9 @@ type TargetSpec struct {
 	OpenOCDCommands  []string `json:"openocd-commands,omitempty"`
 	OpenOCDVerify    *bool    `json:"openocd-verify,omitempty"` // enable verify when flashing with openocd
 	JLinkDevice      string   `json:"jlink-device,omitempty"`
+	ADBPreCommands   []string `json:"adb-pre-commands,omitempty"`
+	ADBPushRemote    string   `json:"adb-push-remote,omitempty"`
+	ADBPostCommands  []string `json:"adb-post-commands,omitempty"`
 	CodeModel        string   `json:"code-model,omitempty"`
 	RelocationModel  string   `json:"relocation-model,omitempty"`
 	WITPackage       string   `json:"wit-package,omitempty"`