Several missing Ops in AllOpsResolver

[ScholliYT]

I found that the AllOpsResolver is missing several already implemented Ops.

This is a list of all currently missing ones:

AddCircularBuffer
AddGather
AddGatherNd
AddIf
AddSlice
AddUnidirectionalSequenceLSTM // unsure if this should be added
AddZerosLike

This list is derived from the differences of micro_mutable_op_resolver and all_ops_resolver using the following command:

diff <(gawk 'match($0, /TfLiteStatus (Add.*\()/, a) {print a[1]}' tensorflow/lite/micro/micro_mutable_op_resolv
er.h) <(gawk 'match($0, /(Add.*\()/, a) {print a[1]}' tensorflow/lite/micro/all_ops_resolver.cc)