[name-registry] Support registering an application

[tahpot]

Add a new method registerApp(did: string, ownerName: string, appName: string, metadata: string[]). This registers an application as being owned by a given did and associates a domain name with it.

For example; Register the Verida: Vault application context to be controlled by a Verida did with metadata:

{
  domain: 'verida.network',
  icon: 'https://assets.verida.network/icon/png'
}

Requirements:

• The registerApp() request must be signed by the owner did. Throws invalid request signature.
• A did can register multiple applications, but all applications they register must have the same ownerName. Throws did is associated with a different owner.
• The combination of ownerName and appName must be unique. Throws application already exists error.
• Both ownerName and appName must only contain alphanumeric characters (including spaces). Throws invalid owner or application name error.
• metadata.domain is required, throws domain is required error
• metadata.domain must be all lower-case and match the valid characters for a domain name. Throws invalid domain format error.
• The did must provide $APP_FEE VDA tokens as a fee for registering an application. These tokens can be withdrawn by the smart contract owner. Throws insufficient tokens provided error.
• metadata is an array of key / value pairs

Add a new method getApp(ownerName: string, appName: string). This returns the did and metadata.

Requirements:

• If the combination of ownerName and appName is not found, throws application not found error.

Add a new method deregisterApp(did: string, ownerName: string, appName: string). This de-registers an application.

Requirements:

• The deregisterApp() request must be signed by the owner did. Throws invalid request signature
• If the combination of ownerName and appName is not found, throws application not found error.

Add a new method updateApp(did: string, ownerName: string, appName: string, domain: string, metadata: string). This updates the metadata for a registered application.

Requirements:

-The updateApp() request must be signed by the owner did. Throws invalid request signature

• The same verification rules apply as registerApp().