Create of a Credentials class in order to have to authenticate only o…

[joaomfrebelo]

…nce.

Create of PrestaSharpNotAuthorazedException and PrestaSharpNotFoundException. Create of a FilterFactory class to facilitate the use of GetByFilter. Create of two method in Functins class to clean strings as in Prestashop Validate:isCatalogName($name) and Validate:isGenericName($name)

[mowcixo]

Hello @joaomfrebelo, thanks for the PR! Do you think you could separate the atomic functionalities in separated PRs? It would be better to review.

Also, with latest changes in master, GenericFactory.cs has conflicts, can you take a look?

[LameuleFR]

Hi @joaomfrebelo

I know it's a bit late but do u think u can finalize this PR?

Benjamin