Get rid of JOIN OSGeo as an option on mantra page

[robe]

I've revise this html page per ​https://git.osgeo.org/gitea/sac/web-cgi-bin/pulls/31

Cause as discussed in that ticket, too many people choose that option and have no clue what that means.

I have taken out the Join OSGeo and replaced with Create Charter Member Profile

[robe]

just a heads up I had intended to only change the mantra page, but when I when I did a make check-ldap-web via ansible, seems other things will be changed:

changed: [ldap_web] => (item=README.md)
changed: [ldap_web] => (item=NEEDMANTRA.html)

changed: [ldap_web] => (item=/home/robe/ansible-deployment/deployment/roles/ldap-web/files/web-cgi-bin/css/pico.min.css)
changed: [ldap_web] => (item=/home/robe/ansible-deployment/deployment/roles/ldap-web/files/web-cgi-bin/css/pico.min.css.map)

TASK [ldap-web : Add /usr/lib/cgi-bin/.mantra] *************************************************************************************************************************************************************************************
changed: [ldap_web]

looking on the server, there are quite a few uncommitted changes. So I'm going to pull the NEEDMANTRA.html from server and cut in my changes.

[robe]

Okay I ended up not using ansible cause too many changes I'm worried about overwriting. So I only checked out the NEEDSMANTRA.html from origin/main overwriting the one on server. That I confirmed only changes are the ones I made.