Update gamedao-protocol according to M2 review

[vayesy]

What needs to be done

Update code to fix issues, noted during Milestone 2 code review from Parity team.

Why it needs to be done

Increase code quality, follow best practices and high standards of the industry.

Acceptance Criteria/Task List

Fix next code issues

Control

• for genesis build block number should be known [source]
• new function for types::Org [source]
• print some logs if sth goes wrong while genesis build [source]
• use is_some to check for set values [source]
• update pay_membership_fee method to accept org and use it's fields [source]
• replace unwrap with error handling [source]
• move event creating from helper to extrinsic [source]
• move event creating from helper to extrinsic [source]
• move benchmarking trait to benchmarks module [source]

Flow

• cleanup storage if campaign doesn't exist [souce]
• replace unwrap with error handling [source]
• replace if, else if with match clause [source]
• replace if, else if with match clause [source]
• move benchmarking trait to benchmarks module [source]

Sense

• replace unwrap with error handling [source]

Signal

• replace unwrap with error handling [source]
• replace unwrap with error handling [source]
• replace unwrap with error handling [source]
• ensure proposal finalization properly handled [source]
• replace unwrap with error handling [source]
• proper error handling for currency call [source]
• proper error handling for currency call [source]
• self-explanatory tests names [source]

Additional context

• Add M2 review comments gamedaoco/gamedao-protocol#112