Resolve: "Log front-end errors to backend for debugging purposes"

Description

Create new backend table uiexception for storing frontend (javascript) errors for debugging. Needed to catch both angular and Cerebral errors, before running through Cerebral signal.

Related issues

Notes to review (code/docs/QA)

Will not post caught errors in front end (typically, when toasts are shown to the user). This is usually caused by backend-requests failing, so will show up in resourcelog.

We store Cerebral state in the database, which can grow quite large. We can leave this to administrators of ELLA to deal with, or we could implement e.g. some magic triggers to delete data older than e.g. 30 days. Thoughts are welcome.

Tests

General

• Tests have been added that prove my fix is effective or that my feature works
• Related tests have been modified/removed

Hypothesis testing:

• Soak testing has been done
• Distribution between positive / negative cases has been checked

Database

• Includes changes to database schema
• Includes necessary database migrations

Configuration

• Includes changes to configuration
• Includes configuration migration instructions in documentation

Merge checklist

• Self-review of code has been performed.
• Feature review and validation against specification has been performed (if applicable). Apply label: QAdone
• Need for documentation has been evaluated and, if necessary, updated. Apply label: docsdone
• Code and implementation has been reviewed by other core developer (including any changes based on initial review). Apply label: code reviewdone

Closes #224 (closed)