"ini_read_value" performance issue

[zydjys]

Bug Report

[Summary]
"ini_read_value" has performance problem when parser smartDeviceLink.ini file

Reproduction Steps

[step1]
Execute smartDeviceLinkCore program with strace under embedded linux system;
[step2]
Analysis strace log

• found many file operation unit(open->mmap2->read->close) with smartDeviceLink.ini
  [step3]review source code ini_file.cc profile.cc
• found ini_read_value will be called many many time
• ini_read_value will call std io fopen->fgets->fclose
• file operation unit is caused by function ini_read_value

Expected Behavior

• the frequencely file operation unit will cause performance issue under embedded linux system if the cpu & volatile memory io is not very powerful.
• when parse smartDeviceLink.ini file : open ini file->and parse all the tag to Profile Class ->close the file
• smartDeviceLinkCore get config tag from Profile class directly;

OS & Version Information

• OS/Version: [all]
• SDL Core Version: [all]
• Testing Against: [sdl_core]

Test Case, Sample Code, and / or Example App

see "ini_read_value" in ini_file.cc

[iCollin]

Closed via #3688