API:  make inplace= arguments take their default value from a global option
#### Code Sample, a copy-pastable example if possible

propose something like this:

```python
pd.set_option('mode.inplace_operations_default', True)
```
#### ~Problem~ Proposal description

My team routinely works with DataFrames of 50GB and up where forgetting `inplace=True` on mutating operations quickly becomes detrimental to shared resources.  We would like to be able to default all operations with an inplace argument to True and be forced to explicitly allow copies if needed.  The proposal is to use a global option to determine the default inplace value vs. making it false in each function/method.  It seems like this should be transparent to the overall Pandas community which expects `inplace=False` semantics (still the default) but gives flexibility to "advanced" users.  From what we can tell in the docs, all inplace arguments are currently False, there are no divergent cases which would prevent a single global default.  Even if there were (perhaps in the future), function authors could override the global default with their opposing local default preference (not great for consistency though).

#### Expected Output

If set to True, all functions/methods which can operate inplace will unless explicitly overriden with an `inplace=False` argument.
