For reasons unknown, the logs of a web hook were paginated in memory.
This would result in the "Edit" page of a web hook timing out once it
has more than a few thousand log entries.
This commit makes the following changes:
1. We use LIMIT/OFFSET to paginate the data, instead of doing this in
memory.
2. We limit the logs to the last two days, just like the documentation
says (instead of retrieving everything).
3. We change the indexes on "web_hook_logs" so the query to get the data
can perform a backwards index scan, without the need for a Filter.
These changes combined ensure that Projects::HooksController#edit no
longer times out.
* implemented logging of project and system web hooks
* implemented UI for user area (project hooks)
* implemented UI for admin area (system hooks)
* implemented retry of logged webhook
* NOT imeplemented log remover
