GitBook read-me improvements for installation

We should consider making the following changes to clarify the installation process in the GitBook

A. On server when directing users to managing applications Settings > Apps > Manage Apps Should say Settings > Atlasian Marketplace > Manage Apps.

B. On server install there is a step for: Choose Settings at the bottom of the page, enable development mode, and apply the change. Development mode allows you to install apps from outside of the Atlassian Marketplace.
This is not applicable to server instances and no such change is needed for the installation. Please remove.

C. On Server install the following steps are listed:
1. Upload the OBR file you downloaded earlier.
2. Once the app is installed, press Configure to open the configuration page.

Please add info to step 1. explicitly telling not to add my from URL yet in this modal. Since I've already seen this value earlier it is confusing to me if I should just save it in the field along with the uploaded file.

The issue identifies the GitBook installation documentation as the entry point; find the server-install section and compare steps A–C against the current text. Update the Apps path, remove the development-mode instruction, and clarify that the From URL field should remain empty during OBR upload. Done means all three requested corrections are visible in the published installation guide.