build size-check enhancement (#5485)

build size-check enhancement (#5485)

* build size-check enhancement

Changed to display a warning when the free size of compilation result is less than 512 bytes.

* update message.mk

* add SIZE_MARGIN variable, change default margin 512 to 1024

for Example.
```
$ make SIZE_MARGIN=2048 crkbd:all
$ make crkbd:all ## mergin is 1024
```

* Update message.mk

change message to ‘approaching the maximum’

Co-Authored-By: mtei <2170248+mtei@users.noreply.github.com>