Proposal to remove (for now) the sis-webapp module

[Martin Desruisseaux]

Hello all

The application/sis-webapp module was excluded from Apache SIS 1.0 
release. This module has not been maintained for 7 years. It has been 
reported a few years ago that is was not working anymore, because of 
links to online data providers that changed (possibly also the protocol 
changed; I did not checked). It also has some links to incubator. Now I 
propose to remove the code, but keep the module as an empty placeholder 
for future developments. The reason for removing this code is that this 
module is the only one using the QuadTree class, and removing sis-webapp 
would make easier to resume the development of QuadTree.

Any objection? If I heard none, I will assume lazy consensus given that 
the code would still in Git history and can easily be extracted back 
when work on sis-webapp would resume.

    Martin