[init] Update weight initializations

[init] Update weight initializations

Add proper bias initialization than just bias_init_zero
Update weight_ini to weight_initializer
Add zero initializer to the list of supported initiailizers

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

Signed-off-by: Parichay Kapoor <pk.kapoor@samsung.com>