Check that user-supplied contract name format is valid before issuing contract initialization requests to node.

[vikt0r0]

Description

The client currently allows for issuing contract initialization transactions with contract names that have an invalid format. Instead the client should validate the contract name to ensure that it conforms to format expected by the node.

Steps to Reproduce
Issue contract init <module> --contract contains.invalid.char on a contract module.

Expected Result

$ contract init <module> --contract contains.invalid.char
Invalid contract name 'contains.invalid.char' specified. <description-of-valid-contract-name>

Actual Result

$ contract init <module> --contract contains.invalid.char
Initialize contract 'contains.invalid.char' from module 
<...>
Transaction '7c98d8bbeca7ea3800246fce6e7aa1746582836c79859b25005295deeff429c8' sent to the baker.
Waiting for the transaction to be committed and finalized.
<...>
Transaction rejected: serialization failed.
[13:04:15] Waiting for the transaction to be finalized......
Transaction is finalized into block d03f20e44480c66340e8a8555c10ecec7bd2ae434255170d640b7a87a054941c with status "rejected" and cost 0.482143 CCD (231 NRG).
Transaction rejected: serialization failed.
[13:04:30] Transaction finalized.
Error: Contract initialisation failed: Serialization failed.

[Bargsteen]

We can use Wasm.isValidInitName to check this.