Move SAH pool configuration options from the library-level config to a config passed to the VFS install routine. Extend and document the PoolUtil object.

FossilOrigin-Name: d2ed99556fa1f40994c1c6bd90d1d5733bebc824b1ebfabe978fae9e18948437

ext/wasm/api/sqlite3-api-prologue.js

@@ -91,21 +91,6 @@
    - `wasmfsOpfsDir`[^1]: Specifies the "mount point" of the OPFS-backed
      filesystem in WASMFS-capable builds.
 
-   - `opfs-sahpool.dir`[^1]: Specifies the OPFS directory name in
-     which to store metadata for the `"opfs-sahpool"` sqlite3_vfs.
-     Changing this name will effectively orphan any databases stored
-     under previous names. The default is unspecified but descriptive.
-     This option may contain multiple path elements,
-     e.g. "foo/bar/baz", and they are created automatically.  In
-     practice there should be no driving need to change this.
-
-   - `opfs-sahpool.defaultCapacity`[^1]: Specifies the default
-     capacity of the `"opfs-sahpool"` VFS. This should not be set
-     unduly high because the VFS has to open (and keep open) a file
-     for each entry in the pool. This setting only has an effect when
-     the pool is initially empty. It does not have any effect if a
-     pool already exists.
-
 
    [^1] = This property may optionally be a function, in which case
           this function calls that function to fetch the value,
@@ -158,8 +143,7 @@ globalThis.sqlite3ApiBootstrap = function sqlite3ApiBootstrap(
   [
     // If any of these config options are functions, replace them with
     // the result of calling that function...
-    'exports', 'memory', 'wasmfsOpfsDir',
-    'opfs-sahpool.dir', 'opfs-sahpool.defaultCapacity'
+    'exports', 'memory', 'wasmfsOpfsDir'
   ].forEach((k)=>{
     if('function' === typeof config[k]){
       config[k] = config[k]();