Install libsqlite3-mod-spatialite by default

[jnm]

I know it's documented in the README, but I don't think saving less than 6 MB of image size is worth the hassle.

root@kobocat:/srv/src/kobocat# apt install libsqlite3-mod-spatialite
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  libsqlite3-mod-spatialite
0 upgraded, 1 newly installed, 0 to remove and 47 not upgraded.
Need to get 1,219 kB of archives.
After this operation, 5,904 kB of additional disk space will be used.

[jnm]

I mean, we install vim inside the image, for goodness' sakes 😊

While we're at it, we should install less: more just really doesn't cut the mustard. Anyone else have a pet peeve about missing utilities inside the image?

[jnm]

For less:

After this operation, 288 kB of additional disk space will be used.