Update to SQLite 3.51.1, improve build script

- Update source to 3.51.1 amalgamation
- Automatically generate module.prop in Get-SQLiteSource.ps1
- Move Get-NDK to submodule

Author: TheFreeman193

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "GetNDK"]
+	path = GetNDK
+	url = git@github.com:TheFreeman193/GetNDK

Get-NDK.ps1

@@ -12,7 +12,9 @@ param(
     [Parameter(Mandatory, ParameterSetName = 'Specific')]
     [version]$Version,
 
-    [string]$SourceDir = $(Join-Path $PSScriptRoot 'src')
+    [string]$SourceDir = $(Join-Path $PSScriptRoot 'src'),
+
+    [string]$ModuleProp = $(Join-Path $PSScriptRoot 'module_template/module.prop')
 )
 begin {
     function Get-SQLiteVersionCode {
@@ -93,6 +95,20 @@ process {
         Remove-Item $Extracted[0] -Force -Recurse
         if (-not $?) { return }
     }
+
+    $PropText = (@'
+id=sqlite3-android
+name=SQLite3 for Android
+version={0}
+versionCode={1}
+author=TheFreeman193
+description=Static up-to-date sqlite3 binaries for Android, built directly from sqlite3 source
+updateJson=https://raw.githubusercontent.com/TheFreeman193/sqlite3-android-module/main/module-update.json
+
+'@ -f $TargetVersion, $FileVersion).Replace("`r`n", "`n")
+    $ModuleDir = Split-Path $ModuleProp
+    if (-not (Test-Path $ModuleDir)) { $null = New-Item -ItemType Directory $ModuleDir }
+    Set-Content $ModuleProp -Value $PropText -NoNewline
     Write-Host -fo Green 'Complete. ' -NoNewline
     Write-Host -fo White "Amalgamated source for version '$TargetVersion' downloaded to '$SourceDir'."
 }

Get-SQLiteSource.ps1

@@ -1,7 +1,7 @@
 id=sqlite3-android
 name=SQLite3 for Android
-version=3.50.2
-versionCode=3500200
+version=3.51.1
+versionCode=3510100
 author=TheFreeman193
 description=Static up-to-date sqlite3 binaries for Android, built directly from sqlite3 source
 updateJson=https://raw.githubusercontent.com/TheFreeman193/sqlite3-android-module/main/module-update.json