Adds new integration [j9brown/victron-mk3-hass]

[j9brown]

Checklist

• [X] I've read the publishing documentation.
• [X] I've added the HACS action to my repository.
• [X] (For integrations only) I've added the hassfest action to my repository.
• [X] The actions are passing without any disabled checks in my repository.
• [X] I've added a link to the action run on my repository below in the links section.
• [X] I've created a new release of the repository after the validation actions were run successfully.

Links

Link to current release: https://github.com/j9brown/victron-mk3-hacs/releases/tag/v0.4.3 Link to successful HACS action (without the ignore key): https://github.com/j9brown/victron-mk3-hass/actions/runs/11138684640 Link to successful hassfest action (if integration): https://github.com/j9brown/victron-mk3-hass/actions/runs/11138684651