fix: disable layered memtable in overwrite mode

[Rachelint]

Rationale

Layered memtable is only designed for append mode table now, and it shouldn't be used in overwrite mode table.

Detailed Changes

• Make default values in config used.
• Add enable field to control layered memtable's on/off.
• Add check to prevent invalid options during table create/alter.
• Add related it cases.

Test Plan

Test manually.

Following cases are considered:

Check and intercept the invalid table options during table create/alter

• enable layered memtable but mutable switch threshold is 0
• enable layered memtable for overwrite mode table

Table options new field layered_enable's default value when it is not found in pb

• false, when whole layered_memtable_options not exist
• false, when layered_memtable_options exist, and mutable_segment_switch_threshold == 0
• true, when layered_memtable_options exist, and mutable_segment_switch_threshold > 0