Individually number each schema upgrade step

1. Unindent conditional upgrade steps
for f in 271 406 452; do sed -i "${f}s/^\t//" schema.php; done

2. Insert 0-padded number for each step
   perl -lne 'if(/^\$upgrade/) {$s=sprintf("%03s",$n++); s/\[\]/[$s]/} print $_' schema.php >x

3. Overwrite schema file and redo indent
   mv x schema.php
   for f in 271 406 452; do sed -i "${f}s/^/\t/" schema.php; done

4. Manually edit the 2nd conditional statements
   - search for '[]'
   - add the same number as the previous upgrade step
Reworded global PHPdoc block in schema.php
Added all missing release markers in schema.php
Convert remaining occurences of 'Array' to lowercase
Install: added ADOdb library version check
Install: special processing for pgsql boolean columns

The upgrade of ADOdb library to version 4.96 with Mantis release
1.1.0 introduced a change in the way type 'L' columns are created
(SMALLINT before, BOOLEAN after).

This requires special handling to fix the database schema, because the
normal schema upgrade steps do not cover it (since from the MantisBT
installer's perspective the column type has not changed).

Fixes #16392
Install: pgsql bool check now handles nullable columns

Issue #16392
Updated ADOdb to include pgsql AlterColumnSQL fixes
WIP: Fix install_date_migrate() for pgsql on ADOdb 5.18

The param count was reset by query execution, causing error in the
function due to mismatched bind parameters when calling db_query_bound()
the second time.

@TODO test, report issue

Fixes #