dts-lib: rework flashing method

[filipleple]

Dasharo version (if applicable)

Dasharo variant (if applicable)

Affected component(s) or functionality (if applicable)

Brief summary

In lib/dts-lib.robot, there is a keyword called Flash Firmware In DTS for flashing that forces flashing with the internal programmer. It needs to be replaced with the more generic keyword that we already have developed in keys-and-keywords/flashrom.robot.

Additional context

[macpijan]

@Psotas Have you done some cleanup in this are in one of your MRs already?

[Psotas]

@macpijan Today I will synchronize with @filipleple regarding two PRs:
Dasharo/open-source-firmware-validation#122
Dasharo/open-source-firmware-validation#130

[Psotas]

@macpijan Should we post issues regarding the test environment here?
Or maybe in these issues: https://github.com/Dasharo/open-source-firmware-validation/pulls

[macpijan]

@Psotas @filipleple We do it here: https://github.com/Dasharo/open-source-firmware-validation/pulls as you can see we have many issues there already.

[macpijan]

I would appreciate it being moved @filipleple
Please also provide links to files rather just names, if possible.

[filipleple]

moved to osfv