evas/cserve2: Reduce repacking and resizing of SHM

evas/cserve2: Reduce repacking and resizing of SHM

These operations have tons of side effects and it's a lot
easier to just avoid doing them. Now, repacking will always
need to happen as applications will add/delete strings and
items, but the less frequent, the better :)

Also, align most arrays & mempools to 32K instead of the
default page size (4K). This will also reduce resizes.