BUG: add names parameter to read_excel
- [x] closes #12870, xref #11874
- [x] tests added / passed
- [x] passes `git diff upstream/master | flake8 --diff`
- [x] whatsnew entry

Currently, set argument `index_col` = `none` can disable taking column names from excel file.
I can also refactor `excel.py` so that old column names can be automatically dropped when `names=names`

**Example**
If we write `DataFrame([[1, 'foo'], [2, 'bar'], [3, 'baz']], columns=['A', 'B'])` to excel and then read,

```
[In] : read_excel(reader, 'DataFrame', names=['A', 'B'])
[out]: 
   A    B
0  a    b
1  1  foo
2  2  bar
3  3  baz
```

```
[In] : read_excel(reader, 'DataFrame', index_col=None, names=['A', 'B'])
[out]: 
   A    B
0  1  foo
1  2  bar
2  3  baz
```
 Will remove test files
 this PR is about a single issue - don't add other things 
 Hey may I ask what is going on with codecov/patch? It pops up some files I didn't touch at all.
 yeah, code cov was set a bit high.

thanks for the PR!
