[activation] Overwrite derivative in softmax

[lhs8928]

Commit 1: [mol attention] adjust tensor lifespan to save memory

 - Modify tensor lifespan of fc_out to FORWARD_FUNC_LIFESPAN
 - remove unused enum updated_state
 - Change param enum name from AttentionParams to MoLAttentionParams

Signed-off-by: hyeonseok lee <[email protected]>

Commit 2: [activation] revise softmaxPrime to overwrite incoming derivative

 - Revise softmaxPrime to overwrite incoming derivative by using additional temp memory
 - Remove attention_score tensor in attention/multi_head_attention layer
 - Reuse temporary tensor for softmax in mol attention layer

close #1986

Signed-off-by: hyeonseok lee <[email protected]>

[taos-ci]

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