Fix build board info

[tannewt]

Use board mapping instead of looking for directories

[Neradoc]

Alias boards get double the versions, because they are already in board_mapping.
So you don't need the inner loop on alias:

    for board_id, board_info in board_mapping.items():
        if board_id not in current_info:
            changes["new_boards"].append(board_id)
            current_info[board_id] = {"downloads": 0, "versions": []}
        new_version = {
            "stable": new_stable,
            "version": new_tag,
            "languages": languages,
            # add modules, extensions, frozen_libraries explicitly
            "modules": support_matrix[board_id]["modules"],
            "extensions": support_matrix[board_id]["extensions"],
            "frozen_libraries": support_matrix[board_id]["frozen_libraries"],
        }
        current_info[board_id]["downloads"] = board_info["download_count"]
        current_info[board_id]["versions"].append(new_version)

With this, it seems all good from what I've been able to see by comparing to the last version on cp.org (with more boards and new modules as expected).