SCons: Unify tools/target build type configuration

Implements https://github.com/godotengine/godot-proposals/issues/3371.

New `target` presets
====================

The `tools` option is removed and `target` changes to use three new presets,
which match the builds users are familiar with. These targets control the
default optimization level and enable editor-specific and debugging code:

- `editor`: Replaces `tools=yes target=release_debug`.
  * Defines: `TOOLS_ENABLED`, `DEBUG_ENABLED`, `-O2`/`/O2`
- `template_debug`: Replaces `tools=no target=release_debug`.
  * Defines: `DEBUG_ENABLED`, `-O2`/`/O2`
- `template_release`: Replaces `tools=no target=release`.
  * Defines: `-O3`/`/O2`

New `dev_build` option
======================

The previous `target=debug` is now replaced by a separate `dev_build=yes`
option, which can be used in combination with either of the three targets,
and changes the following:

- `dev_build`: Defines `DEV_ENABLED`, disables optimization (`-O0`/`/0d`),
  enables generating debug symbols, does not define `NDEBUG` so `assert()`
  works in thirdparty libraries, adds a `.dev` suffix to the binary name.

Note: Unlike previously, `dev_build` defaults to off so that users who
compile Godot from source get an optimized and small build by default.
Engine contributors should now set `dev_build=yes` in their build scripts or
IDE configuration manually.

Changed binary names
====================

The name of generated binaries and object files are changed too, to follow
this format:

`godot.<platform>.<target>[.dev][.double].<arch>[.<extra_suffix>][.<ext>]`

For example:
- `godot.linuxbsd.editor.dev.arm64`
- `godot.windows.template_release.double.x86_64.mono.exe`

Be sure to update your links/scripts/IDE config accordingly.

More flexible `optimize` and `debug_symbols` options
====================================================

The optimization level and whether to generate debug symbols can be further
specified with the `optimize` and `debug_symbols` options. So the default
values listed above for the various `target` and `dev_build` combinations
are indicative and can be replaced when compiling, e.g.:

`scons p=linuxbsd target=template_debug dev_build=yes optimize=debug`
will make a "debug" export template with dev-only code enabled, `-Og`
optimization level for GCC/Clang, and debug symbols. Perfect for debugging
complex crashes at runtime in an exported project.

platform/web/emscripten_helpers.py

@@ -38,7 +38,7 @@ def create_engine_file(env, target, source, externs):
 
 
 def create_template_zip(env, js, wasm, worker, side):
-    binary_name = "godot.tools" if env["tools"] else "godot"
+    binary_name = "godot.editor" if env.editor_build else "godot"
     zip_dir = env.Dir("#bin/.web_zip")
     in_files = [
         js,
@@ -58,19 +58,19 @@ def create_template_zip(env, js, wasm, worker, side):
         out_files.append(zip_dir.File(binary_name + ".side.wasm"))
 
     service_worker = "#misc/dist/html/service-worker.js"
-    if env["tools"]:
+    if env.editor_build:
         # HTML
         html = "#misc/dist/html/editor.html"
         cache = [
-            "godot.tools.html",
+            "godot.editor.html",
             "offline.html",
-            "godot.tools.js",
-            "godot.tools.worker.js",
-            "godot.tools.audio.worklet.js",
+            "godot.editor.js",
+            "godot.editor.worker.js",
+            "godot.editor.audio.worklet.js",
             "logo.svg",
             "favicon.png",
         ]
-        opt_cache = ["godot.tools.wasm"]
+        opt_cache = ["godot.editor.wasm"]
         subst_dict = {
             "@GODOT_VERSION@": get_build_version(),
             "@GODOT_NAME@": "GodotEngine",