[Analyzer] Add a way to add inherit properties to element in manifest instead of superclass

### Should this be an RFC?

- [X] This is not a substantial change

### Which package is this a feature request for?

Analyzer (@lit-labs/analyzer)

### Description

Components that inherit other Lit webcomponents don't inherit properties (but just set the `superclass` field). This breaks the compatibility with external tools.
See: https://github.com/break-stuff/cem-tools/issues/69

### Alternatives and Workarounds

CEM analyzer works fine

Start with the @lit-labs/analyzer package and its manifest output, then read the linked cem-tools issue for the compatibility problem. Determine how inherited Lit component properties should be represented without relying only on the superclass field; done means external tools can consume those properties correctly.

Written by the indexing model from the issue text.