Functions to delete loads

**Is your feature request related to a problem? Please describe.**
Related to the Load Combinations request

**Describe the solution you'd like**
Functions available to remove or edit existing loads on existing nodes or members.

**Additional context**
This will be necessary as part of the Load Combinations request. To remove existing loads and replace them with loads from a different LC without having to build an entirely separate model.

The issue names no files, tests, or entry points; begin by locating the existing load and load-combination implementation in the VBA library and review the related Load Combinations request. Define how loads on existing nodes or members can be removed or edited, with completion shown by replacing loads without building a separate model.

Written by the indexing model from the issue text.