PayButton-Server v4.2.1

Implemented misc performance, build, restart, & security improvements.

What's Changed

• [#1049] feat: async and improved initialization by @chedieck in #1050
• feat: update clientPayment status by @lissavxo in #1043
• feat: add client payment table by @lissavxo in #1034
• Added security headers to prevent clickjacking on sign in by @Klakurka in #1068
• feat: separate process to do initial syncing by @chedieck in #1065
• feat: job to clean up pending old payments by @chedieck in #1066

Full Changelog: 4.2.0...4.2.1