Global unique templateId of compiled contract

[greenhat]

Motivation

• when contract code or embedded parameter changes it may brake the assumptions used at call sites;
• identifying the exact contract by the users;
  The contract id should change is any code or embedded parameter name changes. However, changes in embedded parameter values should not change the id. We're identifying the contract template and not the parametrized contract instance.

Implementation

Hash of:
serialized contract template (ergo tree with placeholders instead of constant values)

[greenhat]

Actually, it has nothing to do with compiler and it should be in sigma as ErgoTree.templateId.