feat: support for changing height or width only

[HunterXing]

feat

Add 'isHorizontalResize' and 'isHorizontalResize' attributes to support changing height and width only.
The premise is static is false.

usage

<grid-item class="vue-grid-placeholder"
                   :x="x"
                   :y="y"
                   :w="w"
                   :h="h"
                   :i="i"
                   :is-horizontal-resize="true"
                   :is-vertical-resize="true"
                   >
</grid-item>

result