Image/File Blob Support

[ruddell]

Describe the bug

Entity fields for ImageBlob and AnyBlob should have an image/file upload field rather than a text field.

Instructions To reproduce

Generate an entity with an ImageBlob and attempt to upload an image.

[ganadara135]

I know you are busy. Anyway I add my code for someone. I deal with this problems like below. I think you can generate more better than this.

----------------------- 'jhi-image-input.js' ----------------------------------------------- https://gist.github.com/ganadara135/6871c1ce9256a074abb3c720ce4c4142

--------------------jhi-form-field.js------------------------------------------ https://gist.github.com/ganadara135/0b44c8ebd33c1a3cc09cab12149df928

[mraible]

@DanielFran https://opencollective.com/generator-jhipster/expenses/92828

[pascalgrimaud]

@mraible : approved