fix(#392 | typesync api): move @graphprotocol/typesync Mapping api into @graphprotocol/hypergraph

[cmwhited]

Description

After discussion during the sync, we came to the agreement that having the extra @graphprotocol/typesync package for the mapping was additional, over-complicated devex with little gain.

So the decision was made to move the @graphprotocol/typesync functionality into the @graphprotocol/hypergraph package and export it out from there instead.

Resulting change is pretty simple:

• before

import type { Mapping } from '@graphprotocol/typesync/Mapping'

• after

import type { Mapping } from '@graphprotocol/hypergraph/mapping'

The type definition/api are exactly the same.

A quickfollow PR will be coming to use this new export in the create-hypergraph templates

Closes #392