Normalize heading levels for bid and analytics adapters

[bretg]

For both bid adapters and analytics adapters: there are instances where individual adapters are using incorrect markdown heading levels. The layout templates assume certain levels are present in the content provided by the contributor:

The bidder layout wraps the content in H3, so contributor MD files should use H3, H4, H5, ...
The Analytics adapter layout wraps the content in H3, so contributor MD files should use H3, H4, H5, ...

There's room to discuss how the layouts work, which in both cases is:

                <h3>Features</h3>
                {{content}}