Add bash completion script for projinfo

[rouault]

and install it in standard ${prefix}/share/bash-completion/completions directory

Demo:

source ./scripts/projinfo-bash-completion.sh

$ projinfo <TAB><TAB>
EPSG:      ESRI:      IAU_2015:  IGNF:      NKG:       NRCAN:     OGC:       PROJ:

$ projinfo -<TAB><TAB>
-3d                                        --boundcrs-to-wgs84                         --list-crs                                  --searchpaths
--accuracy                                  --c-ify                                     --main-db-path                              --show-superseded
--allow-ellipsoidal-height-as-vertical-crs  --crs-extent-use--grid-check                -o                                          --single-line
--area                                      --dump-db-structure                         --output-id                                 --spatial-test
--authority                                 --hide-ballpark                             --pivot-crs                                 --summary
--aux-db-path                               --identify                                  -q
--bbox                                      -k                                          --remote-data

$ projinfo -o <TAB><TAB>
all        PROJ       PROJJSON   SQL        WKT1:ESRI  WKT1:GDAL  WKT2:2015  WKT2:2019

$ projinfo "NAD83(2011) <TAB><TAB>
NAD83(2011)                                                                NAD83(2011) / New Mexico West
NAD83(2011) / Adjusted Jackson (ftUS)                                      NAD83(2011) / New Mexico West (ftUS)
NAD83(2011) / Alabama East                                                 NAD83(2011) / New York Central
[ ... snip ... ]

$ projinfo EPSG:43<TAB><TAB>
4322 -- WGS 72    4324 -- WGS 72BE  4326 -- WGS 84

[kbevers]

This is absolutely fantastic, Even! Very cool addition, looking forward to trying it when I get the chance.