Preserve whitespace in traceback text

Exception messages sometimes contain detail information in separate lines, for readability in log/console output; this change preserves that readability in Sentry layout.

Example:

```
(TransactionRollbackError) deadlock detected DETAIL: Process 13410 waits for AccessExclusiveLock on relation 9923088 of database 9922762; blocked by process 13156. Process 13156 waits for AccessShareLock on relation 9923080 of database 9922762; blocked by process 13410. HINT: See server log for query details. '\nCREATE TABLE foo (\n\tfk_bar INTEGER NOT NULL, \n\tfk_baz INTEGER NOT NULL, \n\tfk_xyzzy INTEGER...
```

becomes:

```
(TransactionRollbackError) deadlock detected
DETAIL:  Process 13410 waits for AccessExclusiveLock on relation 9923088 of database 9922762; blocked by process 13156.
Process 13156 waits for AccessShareLock on relation 9923080 of database 9922762; blocked by process 13410.
HINT:  See server log for query details.
 '\nCREATE TABLE foo (\n\tfk_bar INTEGER NOT NULL, \n\tfk_baz INTEGER NOT NULL, \n\tfk_xyzzy INTEGER...
```
Merge pull request #1278 from gthb/patch-1

Preserve whitespace in traceback text
Compatibility fix for Oracle's mysql-connector-python

The name of this engine is mysql.connector.django.
Make get_db_engine() return 'mysql', not 'django'.
Hide "Create a New Team" button if user can't create teams
Merge pull request #1281 from jaysoffian/master

Compatibility fix for Oracle's mysql-connector-python
Remove is_managed (not present in form)
Fix collection version and score checks
Fix obvious bug
Revert "Fix event navigation in events with same timestamp"

This reverts commit 1db9af8e384dd43b20d3347162503c2e60173f63.

This has performance implications on reasonably sized installs so we need to do something more clever.
More correct javascript
Merge pull request #1282 from jaysoffian/hide-create-team-button

Hide "Create a New Team" button if user can't create teams
Cache all GroupMeta values
Load tags on group details async
More perf improvements to tags
Truncate chained exceptions down to (default) 25 values
Unused code
Correct exc_omitted
Simple test to ensure exceptions render
Correct closing tag
Switch exeptions to pre-wrap