Added Interactive Legend to forestplot Bokeh (arviz-devs#1591)

* Included estimate of probability within ROPE

* Positioned ROPE text and added to CHANGELOG

* Changed color scheme in plot_posterior in bokeh

* Changed size of rope text in posteriorplot bokeh

* Added rope_color and ref_val_color arguments to plot_posterior

* Minor Changes

* Some minor changes

* Added Interactive Legend to forest plot

* Formatted Code

* Updated label generation and fixed some errors

* Updated CHANGELOG

* Minor change

CHANGELOG.md

@@ -7,6 +7,7 @@
 * Added probability estimate within ROPE in `plot_posterior` ([1570](https://github.com/arviz-devs/arviz/pull/1570))
 * Added `rope_color` and `ref_val_color` arguments to `plot_posterior` ([1570](https://github.com/arviz-devs/arviz/pull/1570))
 * Improved retrieving or pointwise log likelihood in `from_cmdstanpy` ([1579](https://github.com/arviz-devs/arviz/pull/1579))
+* Added interactive legend to bokeh `forestplot` ([1591](https://github.com/arviz-devs/arviz/pull/1591))
 
 ### Maintenance and fixes
 * Enforced using coordinate values as default labels ([1201](https://github.com/arviz-devs/arviz/pull/1201))