Use upstream Celery and uWSGI environment variables and defaults

See merge request !165

Merge branch '163-transaction-start_timestamp-and-timestramp-should-support-unix-epoch-times' into 'master'

Resolve "Transaction start_timestamp and timestramp should support unix epoch times"

Closes #163

See merge request !167

Stricter CSP settings by default when not using saas services

Closes glitchtip-frontend#220

See merge request !166

Expose additional files endpoint for org release files

See merge request !164

branch..

Clean up old files task

Closes #129

See merge request !163

Fixes #146

Relative time handling

Closes #151

See merge request !162

not in use)