Proto commits in Xtra-Computing/FedTree

These 13 commits are when the Protocol Buffers files have changed:

Commit:ba4ea5e
Author:cai

Merge branch 'main' into cyz-grpc

The documentation is generated from this commit.

Commit:7df8200
Author:QinbinLi

add party propose and fix float_type

Commit:7f38c32
Author:QinbinLi

add distributed SA

Commit:2539ef7
Author:QinbinLi

add send nodes

Commit:3b20b8d
Author:QinbinLi

improve distributed vertical_fl when label at server

Commit:6b8ee02
Author:cai

fix bug in distributed vertical he

Commit:70d5025
Author:cai

encryption timing completed vertical encryption completed

Commit:48b543f
Author:cai

timing function complete

Commit:8cbf9c4
Author:cai

encryption and batching and parallelization

Commit:7ecb894
Author:YanZhengCai

add encryption to horizontal improve efficiency

Commit:2b33161
Author:YanZhengCai

prototype finished

Commit:1a7c4f6
Author:YanZhengCai

init part success

Commit:6575bc8
Author:yuxuan

add grpc