Implement a migration path from mod_hvp to new H5P activity

User of mod_hvp will be interested to migrate their existing activities to new H5P activity module.  This should include:

• move activity settings to new activity plugin
• move student attempts to new activity
• move student completion status
• move students results/grades and log data.
• Create an admin feature to migrate each instance of mod_hvp to new activity, including hiding old activity instance. Similar to migration feature for old assignment activity.