Ensure that integrations are imported before transformers or ml libs
This PR fixes a problem with some 3rd-party integrations that need to be imported before any transformers or other machine learning framework Python modules.

This PR makes the following changes:

1. Moves `import .integrations` in `__init__.py` before any other transformers imports
2. Moves ML imports in .integrations below 3rd-party imports
3. Used math.ceil() rather than numpy.ceil() as that was overkill

Before PR:

* failed with comet_ml

After PR:

* works with comet_ml
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/7330?src=pr&el=h1) Report
> Merging [#7330](https://codecov.io/gh/huggingface/transformers/pull/7330?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/f5518e56318a79056ba3c80cbece29d9fe98558c?el=desc) will **decrease** coverage by `0.47%`.
> The diff coverage is `88.88%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/7330/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/7330?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #7330      +/-   ##
==========================================
- Coverage   79.30%   78.83%   -0.48%     
==========================================
  Files         181      181              
  Lines       34828    34828              
==========================================
- Hits        27620    27456     -164     
- Misses       7208     7372     +164     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/7330?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/integrations.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9pbnRlZ3JhdGlvbnMucHk=) | `29.00% <87.50%> (ø)` | |
| [src/transformers/\_\_init\_\_.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9fX2luaXRfXy5weQ==) | `99.38% <100.00%> (ø)` | |
| [src/transformers/modeling\_tf\_longformer.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9sb25nZm9ybWVyLnB5) | `16.37% <0.00%> (-82.31%)` | :arrow_down: |
| [src/transformers/modeling\_layoutlm.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19sYXlvdXRsbS5weQ==) | `25.06% <0.00%> (-69.40%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_albert.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9hbGJlcnQucHk=) | `21.62% <0.00%> (-69.31%)` | :arrow_down: |
| [src/transformers/modeling\_marian.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19tYXJpYW4ucHk=) | `60.00% <0.00%> (-30.00%)` | :arrow_down: |
| [src/transformers/configuration\_layoutlm.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb25maWd1cmF0aW9uX2xheW91dGxtLnB5) | `80.00% <0.00%> (-20.00%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_xlm.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl94bG0ucHk=) | `88.37% <0.00%> (-4.87%)` | :arrow_down: |
| [src/transformers/activations.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9hY3RpdmF0aW9ucy5weQ==) | `81.81% <0.00%> (-4.55%)` | :arrow_down: |
| [src/transformers/modeling\_bart.py](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19iYXJ0LnB5) | `93.93% <0.00%> (-0.34%)` | :arrow_down: |
| ... and [18 more](https://codecov.io/gh/huggingface/transformers/pull/7330/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/7330?src=pr&el=continue).
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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/7330?src=pr&el=footer). Last update [f5518e5...0554448](https://codecov.io/gh/huggingface/transformers/pull/7330?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
