adding IMAP folder type controls to folder option widget. Widget uses default

adding IMAP folder type controls to folder option widget. Widget uses default
noselect filtering and sent_subfolders needs to filter noinferiors

fixed sent_subfolder E_NOTICE issues with yearly subfolders and added delimiter
between subfolder base and year folder.

Sent Subfolder Base selection box now lists only folders without noinferiors flag.

Tested on UW.

Some complex folder check is pending.

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@10210 7612ce4b-ef26-0410-bec9-ea0150e637f0