Added text directionality detection to both placeholder and value properties
`placeholder` and `value` are used by InputHeader. Enabling detection on these properties means that text, when entered into an InputHeader can dynamically flip as needed by the input'd text.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
InputHeader's value's RTL-ness, if present, now takes precedence over the placeholder's RTL-ness.
Also improved the initialization logic.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Reduced duplication of running code and supported extreme edge cases.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Corrected a UX edge case: setting value, removing value, placeholder's RTL-ness isn't re-evaluated.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Merge pull request #1654 from enyojs/BHV-14938-blakestephens

BHV-14938: Added text directionality detection to placeholder and value properties

Looks good!

Reviewed-by: Aaron Tam (aaron.tam@lge.com)