Define filecoin top level capability

[fforbeck]

Define filecoin top level capability so it is easy to delegate all of them at once:
e.g.

w3up/packages/capabilities/src/store.js

Lines 24 to 32 in a3af226

	export const store = capability({
	can: 'store/*',
	/**
	* DID of the (memory) space where CAR is intended to
	* be stored.
	*/
	with: SpaceDID,
	derives: equalWith,
	})

Add the top capability (*):

• https://github.com/storacha/w3up/blob/main/packages/capabilities/src/filecoin/storefront.js

• w3up/packages/capabilities/src/types.ts

  Line 894 in a3af226

  FilecoinOffer['can'],