Visual validation of inbound filters and advanced data scrubbing rules

### Problem Statement

To write new inbound filters or data scrubbing rules, as a user I have to:

1. Read the docs to understand the DSL.
2. Guess the right string for the filter/rule.
3. Wait for some time until Sentry applies the filters/rules.
4. Hope the filter was right and filters out exactly what I expected. If not, go back to step 1 and see what I missed.

This has two problems:

1. There's no immediate way to tell whether the filter matches the events I have in mind. The feedback loop for new attempts is slow, so I may not want to go through the whole process again or I give up, and reach out for help.
2. The filter is generic enough and filters out events other developers are interested in. I don't look at other issues, so I can't tell if the impact is too big.

Advanced data scrubbing (including Safe Fields) is more complex, increasing the area of the two problems above.

### Solution Brainstorm

For inbound filters:
- A visual way to pick an event and see whether the filter matches. "Does the new filter discard future events like this one?"
- Run the filters on all events in the project and see what issues are impacted. "What other issues will this filter discard?"
- If the filter is very generic (e.g. `Unhandled Error: *`), a warning that the filter could have a bigger impact than desired.

Advanced data scrubbing is more granular, picking an event and sentry presenting the diff of applying (or not) the rules, including Safe Fields, is good enough.

### Product Area

Unknown