Set `compat.fiber_slice_default` to `new` by default

[LeonidVas]

Link to the discussion.

The fiber_slice_default compat option (introduced in PR tarantool/tarantool#8338) controls the default value of the max fiber slice (see tarantool/doc#3057 for docs). The old behavior is no slice limit. The new behavior is to log the warning if a fiber hasn't yielded for more than 0.5 seconds and raise an error if a fiber hasn't yielded for more than 1 second. In Tarantool 2.x we use the old behavior. We'll switch to the new behavior in Tarantool 3.x, but we should enable the slice limit in the default cartridge template.

Duplicate of (tarantool/cartridge-cli#755)