[Custom] Add actual example

[Custom] Add actual example

**Changes proposed in this PR:**
- Add an example to create the custom layer to be used with ini
- Add an example to create the custom layer to be used with api

**Self evaluation:**
1. Build test: [X]Passed [ ]Failed [ ]Skipped
2. Run test: [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: Jihoon Lee <jhoon.it.lee@samsung.com>