karmada-scheduler: merge scalescheduling with normal scheduling

[Garrybest]

What type of PR is this?
/kind feature

What this PR does / why we need it:
Now scale scheduling has a particular process without share the same logic with normal scaleduling. Here shows some problems:

1. The code is too complicated.
2. If a new cluster has added, the scale scheduling could not make the new one as a candidate because the process does not contain a replica estimation step. The result of candidate clusters are based on the previous scheduling result. See here

Now the two steps have been merged. Actually, the first scheduling is a special kind of scaling up. There is no need to separate the two kinds.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

[Garrybest]

The PR has been divided into 3 commits.

1. Merge scale scheduling with normal scheduling. This is the most important change.
2. Delete scale scheduling. I just delete the scale scheduling logic from scheduler, it is almost full of deletion codes.
3. Unit test change for function parameters change. This is not that important.

[Garrybest]

/cc @RainbowMango @gf457832386 @BDXGD @mrlihanbo

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[RainbowMango]

Now the two steps have been merged. Actually, the first scheduling is a special kind of scaling up. There is no need to separate the two kinds.

Same idea with #988 (comment).

[RainbowMango]

cc @dddddai

[qianjun1993]

As we merged the logic of first schedule and scale schedule, Maybe we do not need retain the cluster with 0 replicas in scheudlue result.

karmada/pkg/scheduler/core/division_algorithm.go

Line 146 in bbf113a

desireReplicaInfos[cluster] = 0

[RainbowMango]

Review still on-going.

We are lacking proper abstractions, the code becomes difficult to understand, now. :(

[Garrybest]

We are lacking proper abstractions, the code becomes difficult to understand, now. :(

Emmm, that's right, too complicated😵‍💫. But this PR could help make it better because we merge the two cases.

[RainbowMango]

Yes, this PR is a relief.
By the way, can you solve the conflicts, we just merged #988, and I wish this PR is the next.

[RainbowMango]

/lgtm
/approve

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