ENH: `styler.render.encoding` option
This pandas option is added to allow the `Styler` options to be independent from the others. See #41395

 - [x] add option
 - [x] add tests
 - [x] whats new
 - [x] update function docstrings `to_latex` and `to_html`
 
will update styler user guide (do as a follow on).

encoding also applies to saving to files where appropriate, as well as HTML metatag

```python
>>> df = pd.DataFrame([[1,2],[3,4]])

>>> print(df.style.to_html(doctype_html=True)[:76])
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<style type="text/css">

>>> pd.options.styler.render.encoding = "ANSI"
>>> print(df.style.to_html(doctype_html=True)[:75])
<!DOCTYPE html>
<html>
<head>
<meta charset="ANSI">
<style type="text/css">
```
