The LOFAR Two-Meter Sky Survey: Deep Fields Data Release 1 I. Direction-dependent calibration and imaging by Tasse, C, Shimwell, T, Hardcastle, MJ, O'Sullivan, SP, van Weeren, R, Best, PN, Bester, L, Hugo, B, Smirnov, O, Sabater, J, Calistro-Rivera, G, de Gasperin, F, Morabito, LK, Roettgering, H, Williams, WL, Bonato, M, Bondi, M, Botteon, A, Brueggen, M, Brunetti, G, Chyzy, KT, Garrett, MA, Guerkan, G, Jarvis, MJ, Kondapally, R, Mandal, S, Prandoni, I, Repetti, A, Retana-Montenegro, E, Schwarz, DJ, Shulevski, A, Wiaux, Y