cleanup: remove all legacy dagster deployment code

[ptab]

Self-explanatory title 🧹

It's kinda scary how this PR changes literally 0 lines of test code 🙈

Depends on:

• https://github.com/Vandebron/github-actions/pull/349
• https://github.com/Vandebron/scripting/pull/4656

[github-actions]

Package	Line Rate	Health
src.mpyl	85%	➖
src.mpyl.cli	63%	❌
src.mpyl.plan	100%	✔
src.mpyl.projects	75%	❌
src.mpyl.steps	94%	➖
src.mpyl.steps.deploy	88%	➖
src.mpyl.steps.deploy.k8s	95%	➖
src.mpyl.steps.deploy.k8s.resources	97%	➖
src.mpyl.utilities	92%	➖
src.mpyl.utilities.dagster	72%	❌
src.mpyl.utilities.docker	82%	➖
src.mpyl.utilities.helm	100%	✔
src.mpyl.utilities.http_client	85%	➖
src.mpyl.utilities.logging	78%	❌
src.mpyl.utilities.pyaml_env	100%	✔
src.mpyl.utilities.repo	97%	➖
src.mpyl.utilities.subprocess	76%	❌
src.mpyl.utilities.yaml	100%	✔
Summary	87% (2010 / 2313)	➖

Minimum allowed line rate is 79%