The first of two parts covering the 1988 Imagine: John Lennon documentary.         Despite the release of the Beatles catalog the previous year, all was not well in the land of Lennon.      The Albert Goldman character assasination disguised as biography came out early in 1988, and some fans still held hard feelings over Yoko's approval of the Nike "Revolution" spot.      The best solution would be to bring John's two biggest strengths - his life, and his music to the fore.        Both would be serviced by a major motion picture including a peek into the Lennon video archives, new interviews with people close to Lennon (but NOT the other three Beatles), unheard (to that point) Lennon home demos and remixed versions of classic Lennon and Beatles tunes,     This week the first half of the film, covering most of the Beatles years and the Tittenhurst Park footage.       Continued next week!