Admin customization of encounter search map

[TanyaStere42]

Feature description and context

The map focus settings are used broadly through the site and shape user experience. As site admins onboard new users, they may need to adjust the default map position. As part of the modernization efforts for the site, we need to replace configuration properties with admin-accessible tools in the UI so site admins are not required to dig into configuration files.

Note: can be finished in place of #802

Feature sign-off requirements

• page: react/admin/SiteSettings
• map with pan and zoom capabilities loads current zoom (site default is centerLat=-33.3827109, centerLong=115.2504794, mapZoom=4)
• Save button updates centerLat, centerLong, and mapZoom in the commonconfig.properties file
• Save button POSTs the same information to the database for use by react pages

Design

Note: If languages controls do not already exist (see #704), do not implement tab structure. design is an approximation; use wildbook's custom components or standard bootstrap components.

[naknomum]

proposal: use this as opportunity to initiate very basic db-based configuration/settings class, and store values there instead. (and this would feed into values shown via api site-settings, for FE usage.)

further, existing jsp code could use these values as well by refactoring the methods called such as getCenterLat/Lon():

                let centerLat = '<%=CommonConfiguration.getCenterLat(context)%>';
                let centerLong = '<%=CommonConfiguration.getCenterLong(context)%>';