Migrate specifications to global namespace (#780)
* Migrate specifications to global namespace
Previously @links in specification documents required a corresponding import for esdoc tooling to work. This changes
to a global "MatterSpecification" namespace. Since it only contains types a global seems OK. Also changes to a
slightly more concise hierarchical naming convention.
* Minor doc tweaks
Remove spec from matter.js typedoc config
Move Specifications.d.ts to "dts" folder
* Delinkify non-imported reference to clusters
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Co-authored-by: Ingo Fischer <github@fischer-ka.de>
