Signing takes a lot if there is a lot of identities

[ajunge]

Signing in an environment with a lot of identities is very slow. Basically because

async getIdentity(did: string): Promise<AbstractIdentity> {
    const identities = await this.getIdentities()
    const identity = identities.find(item => item.did === did)
    if (identity) {
      return identity
    } else {
      return Promise.reject('No identity: ' + did)
    }
  }

gets all the identities first and then select one.

Maybe is easier something like:

async getIdentity(did: string): Promise<AbstractIdentity> {
    let identity: AbstractIdentity;
    for (const identityProvider of this.identityProviders) {
      const providerIdentity = await identityProvider.getIdentity(did);
      if(providerIdentity) identity = providerIdentity;
    }
    if (identity) {
      return identity
    } else {
      return Promise.reject('No identity: ' + did)
    }
  }

is much faster, and scales better, since the providers number is constant.