Place all ungrouped dependencies into a single pull request

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Feature description

I would like updates to all dependencies that don't match any group definitions to go into a single pull request. Currently, to achieve this requires creating an "other" group and explicitly listing each of these dependencies in it. This creates a maintenance burden when dependencies change.

One way of achieving this is to (optionally) constrain each dependency to belong to a single group. Groups should be defined in priority order, so if a dependency matches multiple groups, it will belong to the one highest in the list. One could then define an `other` group at the end with a pattern of `"*"` to group up any unmatched dependencies.

There is another benefit to mutually exclusive groups: If group 1 is `*prettier*` and group 2 is `*eslint*`, you don't need to use `exclude-patterns` to prevent `eslint-plugin-prettier` appearing in both groups.

The above is just a suggestion. There may be other ways to solve this problem.

No files, tests, or entry points are named. Start by locating the dependency grouping logic and its configuration handling, then determine whether mutually exclusive, priority-ordered groups or another approach best groups unmatched dependencies; done means unmatched dependencies share one pull request without explicit maintenance of every dependency.

Written by the indexing model from the issue text.