pm: tx cost checks

[yondonfu]

What does this pull request do? Explain your changes. (required)

This PR adds checks on the orchestrator to:

• Ensure that the estimated ticket redemption tx cost can be covered by the advertised ticket face value. At the moment, when the default ticket face value is higher than the broadcaster's max float (derived from its reserve), the ticket face value is adjusted to match the broadcaster's max float. A check is added to require that the broadcaster's max float >= the estimated ticket redemption tx cost
• Ensure that tickets are only redeemed if their face value would cover the estimated ticket redemption tx cost

This PR focuses on adding the above missing checks and leaves further configuration to be addressed separately.

See #1603 for more details.

Specific updates (required)

See commit history.

How did you test each of these updates (required)

Added unit tests.

Checklist:

• README and other documentation updated
• Node runs in OSX and devenv
• All tests in ./test.sh pass

[darkdarkdragon]

LGTM

[jailuthra]

LGTM as well!

(although I do not fully understand the details of ticket redemption, but the changes and tests seem to match the solution described in #1603)