Currently we use arrays allocated on heap for initializing
available locales and dictionaries.

This patch encapsulates all the different objects
related to a dictionary into a strcut dictItem.

unique_ptr is used for hunspell, also uses o3tl::make_unique for creating them.
Used 'reserve' for better memory allocation of vector.
Removed unused member and local variables.

Change-Id: I6309c681790cfec4ee9b11119937063bc414cf1f
Reviewed-on: https://gerrit.libreoffice.org/48109Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>