Integrate CSL with the wrapper

[MSzalowski]

What

Integrate CSL library into wrapper

How

To make the already defined actions used across govtool pillars wrap up some commonly used CSL services into one Provider & Service (including eg.: cert builders, transaction builders and so on).

• Such service should be stateless to make it able to use on the server-side frameworks.

Logic might be reused from the current govtool implementation (having in mind that copy&paste is rather not intended as current solution requires refactor)

• Should be part of GovTool wrapper based on this issue.

• Wallet connection should be separate (as it is already done with the wallet-connector package)

[MSzalowski]

I've left a review comments under the pull request.

[pmbinapps]

No negative impact on functionality was noticed.