key_frame_interval capi option inconsistently named with cli

[tdaede]

The options for keyframe interval via capi are named "key_frame_interval" and "min_key_frame_interval", but this does not match either the cli (which is "keyint and "min_keyint"), nor the config struct (which is "max_key_frame_interval" and "min_key_frame_interval", and has different semantics regarding max = 0).

Given the semantics we should probably accept the CLI names of these parameters.

Version:

rav1e 0.6.6 (UNKNOWN) (release)
Compiled CPU Features: fxsr,sse,sse2
Assembly: Enabled
Threading: Enabled
Unstable Features: Enabled
Compiler Flags: -Copt-level=3-Cdebuginfo=2-Ccodegen-units=1-Cstrip=none-Cforce-frame-pointers=yes-Clink-arg=-Wl,-z,relro-Clink-arg=-Wl,-z,now-Clink-arg=-specs=/usr/lib/rpm/redhat/redhat-package-notes--cap-lints=warn