Make the constructor taking satoshi as parameter from the Amount class private

Summary:
This remove assumption from the codebase that Amunt are denominated in satoshi.

Depends on D1718, D1711, D1712 and D1722

Test Plan:

make check
./test/functional/test_runner.py --extended

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1723