feat(height, width): accept string

[rbalet]

Description

Actually, we're obligated to pass a variable, as string isn't accepted.
Example :

• valid: [imageHeight]="70"
• invalid: imageHeight="70"

Expected behaviour

Being able to pass a string directly, the component would then handle the type safeties.

Note

I'll be glad to do a PR if this issue is accepted : )

[Cordobo]

Sounds good! Feel free to open your PR against the dev branch