wis2box-ui: turn clustered markers on/off via ENV variable or map toggle

[maaikelimper]

question/feedback from Iran:

_In the previous version (1.0b4), all the stations are displayed on the map at the same time and the status of data reception
can be easily seen, but in the new version, the stations are displayed in a clustered form ( related figures attached to the email).
And to see the reception status, you need to zoom in on each cluster on the map.
Is there any config to display all stations like the previous version? Since, it was more user friendly.
Best Regards,

Zeinab_

[maaikelimper]

Implemented in wis2box-1.0b6 as follows:

New environment-variables WIS2BOX_UI_CLUSTER=false controls the default section