Camera: Use slowJpeg if JPEG minimum duration is less than preview fps

If the minimum duration of JPEG is less than the frame duration derived
from maximum fps, enable slowJpeg mode so that JPEG doesn't slow down
preview.

Cap the default max fps to 30 so that the switch between different
sensor modes can be minimized while still allowing the app to go higher
than 30fps.

Test: Camera1 CTS
Bug: 36692074
Change-Id: If4d367ac587c0f4d3620ca2d25063c5a12ebfceb