v8.0.0

We found that the previous version v7 had problems between mana estimation
and multisignature transactions, because the estimation was done after the
first signature.
Now this concept has been improved and moved to the Transaction class, which
has a more intuitive process and supports multisignatures.

🚀 Features

• adjustRcLimit is a new function in the Transaction class to adjust
  the rcLimit and at the same time recalculate the transaction ID. This function
  could be used by wallets during the estimation of the mana.
• Transaction class now supports the definition of transaction in the
  constructor.
• Documentation improved with examples for mana estimation.
• breaking changes:
  • The rcOptions have been removed from the Signer class and moved to
    Transaction class (see adjustRcLimit).
  • recoverAddresses and recoverPublicKeys from the Signer class
    are now static functions.

🐛 Bug Fixes

• Fix types for receipt and block_receipt