refactor: remove non-portable sync-versions of methods

[AlCalzone]

This PR removes the deprecated synchronous versions of several methods related to:

• CC and message parsing and serialization
• encryption/decryption
• firmware handling

This required moving to Node.js 20 as the minimum - Node.js 22 is LTS.

---

Complete list of API changes:

• The deprecated CommandClass.parse(...): CommandClass and the async CommandClass.parseAsync(...): Promise<CommandClass> methods have been merged into a single signature async CommandClass.parse(...): Promise<CommandClass>. Synchronous parsing of CommandClasses using the parse method is no longer possible.
• The deprecated CommandClass.from(...): CommandClass and the async CommandClass.fromAsync(...): Promise<CommandClass> methods have been merged into a single signature CommandClass.from(...): CommandClass | Promise<CommandClass>. For CCs that support synchronous parsing, this will return a CC instance, otherwise a Promsie that resolves to one.
• The deprecated CommandClass.serialize(...): Bytes and the async CommandClass.serializeAsync(...): Promise<Bytes> methods have been merged into a single signature async CommandClass.serialize(...): Promise<Bytes>. Synchronous serialization of CommandClasses is no longer possible.
• The deprecated CommandClass.mergePartialCCs(...) and the async CommandClass.mergePartialCCsAsync(...) methods have been merged into a single signature async CommandClass.mergePartialCCs(...). Synchronous merging of partial CCs is no longer possible, but this should not affect applications.
• The deprecated Message.serialize(...): Bytes and the async Message.serializeAsync(...): Promise<Bytes> methods have been merged into a single signature async Message.serialize(...): Promise<Bytes>. Synchronous serialization of Serial API messages is no longer possible.
• SecurityManager.generateAuthKeySync and SecurityManager.generateAuthKeyAsync have been replaced with the method SecurityManager.generateAuthKey, which is now purely async
• SecurityManager.generateEncryptionKeySync and SecurityManager.generateEncryptionKeyAsync have been replaced with the method SecurityManager.generateEncryptionKey, which is now purely async
• The property SecurityManager.authKey was replaced with an async method async getAuthKey(): Promise<Uint8Array>
• The property SecurityManager.encryptionKey was replaced with an async method async getEncryptionKey(): Promise<Uint8Array>
• The following methods of the SecurityManager2 class are now async, the corresponding ...Async variants have been removed. Typically applications shouldn't need to use them:
  • setKey
  • generateNonce
  • initializeSPAN
  • initializeTempSPAN
  • nextNonce
  • getMulticastKeyAndIV
  • nextPeerMPAN
• The extractFirmware method is now async, its ...Async counterpart was removed
• The Controller.dsk property was removed in favor of the method async getDSK(): Promise<Uint8Array>