LPS-43009 Hook to support RTL feature in 6.2.x (1st part)

Hey Brian,

In order to make your code review easier, I'll send you the commits for the RTL Hook in 3 blocks. The first one contains the basic support for RTL in the portal. The other two will include the support for RTL in custom plugins and the backport of bug fixes.

Please let me know if you have any questions.

Thanks

@juliocamarero