Rename : package name golang-jamo changed to jamo

Signed-off-by: ymw0407 <[email protected]>

Feat : decomposing hangeul into syllables feature added

- 2 decompose option added
  - jamo option
  - qwerty option
- test code added
- gitignore added

Signed-off-by: ymw0407 <[email protected]>