v1.12.19 for KSP 1.12

What's Changed

• Add reference to online orbit calculator to Sun Sync Satellite contract by @marsh1832 in #1908
• Remove 'Uncrewed' from Lunar Impactor contract name by @marsh1832 in #1907
• Migrate basic RP-0 configs for US2 by @Capkirk123 in #1904
• Rename SNTPPFE config to avoid name conflict by @Capkirk123 in #1917
• Add configs for new Kerbal Atomics parts by @Capkirk123 in #1911
• Configure ROEE ATCRE by @Capkirk123 in #1916
• Add support for new Agena SPS configs by @Capkirk123 in #1921
• Fix a GameEvents leak by @siimav
• Add 'Downtime post mission' difficulty setting by @siimav

Full Changelog: v1.12.18.0...v1.12.19.0