Use PyTensor distributions (#706)

* use pytensor-distributions

* update version

* use numpy functions

* fix docs

* fix docs

Author: aloctavodia

docs/distributions/gallery/discrete_weibull.md

@@ -25,7 +25,7 @@ The Discrete Weibull distribution is predominantly used in reliability engineeri
 Support   :math:`x \in \mathbb{N}_0`
 Mean      :math:`\mu = \sum_{x = 1}^{\infty} q^{x^{\beta}}`
 Variance  :math:`2 \sum_{x = 1}^{\infty} x q^{x^{\beta}} - \mu - \mu^2`
-========  ===============================================
+========  ==========================================
 ```
 
 **Parameters:**

docs/distributions/gallery/weibull.md

@@ -25,7 +25,7 @@ This distribution is widely used in fields like engineering, survival analysis,
 Support   :math:`x \in [0, \infty)`
 Mean      :math:`\beta \Gamma(1 + \frac{1}{\alpha})`
 Variance  :math:`\beta^2 \Gamma(1 + \frac{2}{\alpha} - \mu^2/\beta^2)`
-========  ====================================================
+========  ==========================================
 ```
 
 **Parameters:**