Add Payment Delegation Commands to CLI (#9766)

* Add Payment Delegation Commands to CLI

* add support to allocate a fraction of rewards and delegate to a named
  beneficiary
* new cli commands for get, set, and delete
* expose functionality available in Accounts.so

WIP

* its not clear which account the context applies to
* delete has not been fully tested

[#182759476]
[Test] y
[Review] y

* Complete support for delete and set

* add account parameter that commands are executed for

[finishes #182759476]
[Test] y
[Review] [email protected], [email protected]

* Address code review comments in upstream pr

* upstream pr #9700
* remove commented code
* remove references to fixidity lib in docs
* remove unecessary getter definition

[#182759476]
[Test] y
[Review] m-chrzan

* Add payment delegation unit tests, generate docs

* upstream pr #9700
* test for invalid payment delegation fraction greater than 1
* test that fetched delegation values are equal to values set
* test that deleting delegation clears values
* fix up cli example help
* generate docs for account.md

[finishes #182759476]
[Test] y
[Review] m-chrzan

Co-authored-by: Daniel Swid <[email protected]>
Co-authored-by: Javier Cortejoso <[email protected]>