Getting rid of more CVEs

[hwchase17]

To continue improving LangChain for production applications, we're planning on making the following changes on 10/10/2023:

LLMSymbolicMathChain and LLMBashChain with related bash utilities will be removed from langchain.

These chains will be available in the langchain_experimental package.

In addition, we'll be disabling the ability to use jinja2 style templates:

• jinja2 style templates Disable loading jinja2 PromptTemplate from file. #10252 (CVE GHSA-7gfq-f96f-g85j)

For more context please see: #8043