OpenFilesScreen update

- Remove local types and function from header file
- Reduce OpenFiles_Data to neccessary size
- Print file access mode (r/w/u)
- Fix memory leak on consecutive items without an intermediate file item:

    ==15257==ERROR: LeakSanitizer: detected memory leaks

    Direct leak of 120 byte(s) in 12 object(s) allocated from:
        #0 0x48c864 in strdup (htop/htop+0x48c864)
        #1 0x542f68 in xStrdup htop/XAlloc.c:71:17
        #2 0x50e225 in OpenFilesScreen_getProcessData htop/OpenFilesScreen.c:112:25
        #3 0x50cd17 in OpenFilesScreen_scan htop/OpenFilesScreen.c:141:35
        #4 0x4fd3eb in InfoScreen_run htop/InfoScreen.c:81:35
        #5 0x4d58bb in actionLsof htop/Action.c:361:4
        #6 0x501766 in MainPanel_eventHandler htop/MainPanel.c:80:19
        #7 0x5289fa in ScreenManager_run htop/ScreenManager.c:227:19
        #8 0x4f748e in main htop/htop.c:300:4
        #9 0x7ff73e0d8cc9 in __libc_start_main csu/../csu/libc-start.c:308:16

    SUMMARY: AddressSanitizer: 120 byte(s) leaked in 12 allocation(s).

0 files changed, 0 insertions, 0 deletions