Add link to audit log and relevant entities in Slack integration

[rolodato]

Is your feature request related to a problem? Please describe.

When using the Slack integration, customers are notified of specific actions which are also recorded to the audit log, as described here: https://docs.flagsmith.com/system-administration/audit-logs

The Slack messages do not contain any links to the Flagsmith application. If users want to action on these notifications, they need to manually search for the relevant entities within Flagsmith.

Example notifications:

The feedback here might apply to other integrations, but I am using Slack in my testing.

Describe the solution you'd like.

At a minimum, all Slack messages that have a corresponding audit log entry should include a clickable link to the entry.

It would be convenient to also include links to entities - for example, making the names of features, environments and segments clickable by adding links to them. This could still result in a 404 if a feature/segment/environment was deleted later on, but this is still useful.

Another nice-to-have would be better visual separation between Slack messages. If I have a Slack channel dedicated for this integration, these messages can pile up and it's not immediately obvious where one begins and the other ends. For example, look at this long list of messages and try to find the message boundaries at a glance:

I would consider making the title bold and the detail subheadings like "Environment" and "User" not bold. Something like this:

Messages about things being deleted should only include a link to the audit log, and not a link to the thing since it will most likely be a 404.

Describe alternatives you've considered

Some customers have requested being able to completely customise the messages, but this is a much more complex task and what I've suggested here should cover the vast majority of feedback around the Slack integration. If further customisation is required, we can always refer customers to a custom webhooks integration.

Additional context

No response