change gnome evolution keyboard accels
Solution 1:
I found out myself that I've to remove the comment semicolons in front of the lines in ~/.config/evolution/accels
while evolution is stopped. Then the uncommented lines are respected by evolution. Yet evolution overwrites ~/.config/evolution/accels
but it keeps the edits.
Example of ~/.config/evolution/accels
with a F8 beeing assigned
; (gtk_accel_path "<Actions>/mail/mail-goto-menu" "")
; (gtk_accel_path "<Actions>/mail/mail-folder-select-thread" "<Primary>h")
(gtk_accel_path "<Actions>/mail/mail-to-do-bar" "F8")
; (gtk_accel_path "<Actions>/mail/mail-find" "<Primary><Shift>f")