Enhance LookupFieldDefinition, add secondary fields provision support

[SubPointSupport]

SPMeta2 should allow to provision secondary fields for the lookup field definition.

• [CSOM/SSOM] Site level provision
• [TODO] Web level provision
• [TODO] List level provision
• [CSOM/SSOM] Content type support

Based on the feedback: https://subpointsolutions.uservoice.com/forums/170238-spmeta2-spcafcontrib-ideas-feedback/suggestions/7109388-ability-to-add-secondary-fields-in-lookupfielddefi

[SubPointSupport]

Site level provision implemented for both CSOM/SSOM. Covered by tests:

• CanDeploy_DependentLookupField_OnSite

[SubPointSupport]

Content type support:

• CanDeploy_DependentLookupField_OnContentType