This represents the first task under MDL-79973.

The goals here are:

1. Understand how the data within mod_lti 'lti' table (tool instances) is used.
2. Document which fields can be moved from this table to a generic link (resource link) structure within core_ltix.
   • I.e. which fields are common to all resource links, which fields only apply to the module, and which fields are legacy use only.