Replace logo for Open Tech

[kflemin]

the orange "OGBS" logo on this page: https://seed-platform.org/technical_ally/

should be replaced with the following logo:
https://opentech.eco/wp-content/themes/open/assets/images/logo.svg

[RDmitchell]

@kflemin -- there are several logos that need replacing and at least that needs deleting.

I have started to do that on the user-documentation branch, and once I get that sorted, maybe the changes can be moved over to main.

[anchapin]

We should make a new "logo" branch to do these updates.