Add an ability to retain the log of the script runs

Problem/Motivation

Minimum ACs

• "Batch Op Log" entity that will track the following
• What script ran (string) - the main identifier
• What ran it (drush, UI, hook_updateN, post update, deploy hook, post deploy)
• Who ran it (user entity reference)
• when it started (timestamp)
• when the last operation ocurred (timestamp)
• Whether the operation was completed (boolean)
• Log (long text) - Concat text (appended to by each processOne()} (as though watching in the terminal)
• any caught errors or exceptions (long text)
• Needs a separate "View batch operations log" permission
• Documented in the README

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes