Fix order of SQLite PRAGMAS to allow configurable page_size

[vvysokikh1]

High Level Overview of Change

Fixed the order of application of pragmas when opening SQLite connection. Due to specific pragmas set with commonPragmas, it looks like a page gets allocated in the DB file BEFORE page_size is set, thus locking the page_size to default value 4096.

Context of Change

This issue has no effect before #5135 is merged.

Type of Change

• [ x] Bug fix (non-breaking change which fixes an issue)

Test Plan

1. Run rippled creating brand new transaction.db file with SQLite: Allow configurable sqlite database pragma variables. #5135, setting rippled.cfg to have the following:

...
[sqlite]
page_size = 8192
...

2. After a couple of seconds you should be able to run sqlite command to check the page_size of new transaction.db file:

sqlite3 <path>/transaction.db 'PRAGMA page_size;'

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.2%. Comparing base (b6391fe) to head (915c71f).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #5140   +/-   ##
=======================================
  Coverage     76.2%   76.2%           
=======================================
  Files          760     760           
  Lines        61550   61550           
  Branches      8123    8122    -1     
=======================================
+ Hits         46884   46888    +4     
+ Misses       14666   14662    -4     

Files with missing lines	Coverage Δ
src/xrpld/core/DatabaseCon.h	100.0% <100.0%> (ø)

... and 6 files with indirect coverage changes

[Bronek]

LGTM

[Bronek]

For readers of this PR:

• this is about swapping the order of execution of SQLite PRAGMA statements in commonPragma parameter and pragma parameter
• commonPragma is either nullptr or globalPragma initialised in xrpld/core/detail/DatabaseCon.cpp (look for result->emplace_back)
• the actual PRAGMA statements are constructed from the three strings CommonDBPragma... in xrpld/app/main/DBInit.h
• the problem this PR solves is caused by PRAGMA journal_mode which creates journal file - hence committing page_size to the database, whatever it is at that point
• so if we want a non-default page_size, it needs to be set before PRAGMA journal_mode
• we set page_size in pragma parameter , hence it needs to be processed before commonPragma parameter
• we have not noticed the problem until today because the hardcoded page_size happens to be 4KB, which is identical as the SQLite default
• however there's a PR in flight SQLite: Allow configurable sqlite database pragma variables. #5135 to make page_size configurable and that will, obviously, do not work

FWIW globalPragma is static which is a bad code smell, but changing it belongs to a different PR (refactoring only)

[intelliot]

Important to move these pragmas first so that PRAGMA page_size is executed before PRAGMA journal_mode (which accesses the database and commits the page_size)