Upstream changes
- Revert "cleanup environment variables related to global configuration after instantiating config object"
- Merge branch 'less-leaks' into 'master'
- cleanup environment variables related to global configuration after instantiating config object
- Merge branch 'session-encryption' into 'master'
- spaces to tabs
- we no longer directly modify schema_version in migrations
- if possible, automatically encrypt stored plaintext password for feed on update
- support transparent encryption for feed passwords, bump schema to drop length limit of ttrss_feeds.auth_pass
- drop SESSION-specific stuff and move encrypt/decrypt helpers to a separate class; add a command line flag to generate encryption keys
- rename SODIUM_ENCRYPTION_KEY to SESSION_ENCRYPTION_KEY and move related stuff to Sessions class
- add optional encryption for stored session data using Sodium library
- Merge branch 'allow-session-cookies' into 'master'
- allow setting lifetime to 0 for session cookies