Add key dvpd word summary to dvpi

[mattywausb]

To allow dvpi consuming steps to warn about dvpd syntax, that is not supported or even disregarded, a summary of all used keywords will be added. This will be separated into multiple sections:

Main: keywords that are not field or model related

Source: keywords that are only source structure related (field keywords)

Model: keywords that are model and mapping related

Main and source keywords are only listed as json pathes

• fields.json_path
• fields.value

Model and mapping keywords are listed per stereotype and columns class by prefixing it like the following

• hub:hub_key_name
• hub:business_key/prio_in_key
• sat:parent_table_name
• sat/content:prio_in_diff_hash
• lnk:parent_tables.relation_names