Add flowchart in new extractors/README.md

Adds a mermaid (markdown-formatted) flowchart to show the flow of
execution for the current (shell-script-based) extractor implementation.

Updates the root `.gitignore` file for this project and adds:

- `extractors/.gitignore`
- 'javascript/frameworks/cap/test/.gitignore'

Author: data-douser

.gitignore

@@ -62,6 +62,7 @@ typings/
 
 # Misc
 .DS_Store
+.*.swp
 
 dist/
 tmp/

extractors/.gitignore

@@ -0,0 +1,5 @@
+# Files to ignore under this "extractors" directory
+
+## Ignore the debug directory
+debug/
+

extractors/README.md

@@ -0,0 +1,45 @@
+# codeql-sap-js:extractors/README.md
+
+## CodeQL CDS Extractor : Flowchart
+
+The following flowchart shows the flow of execution for the current implementation of the extractor.
+
+```mermaid
+flowchart TD
+    COM["`export _build_cmd=<br>$(pwd)/extractors/
+javascript/tools/
+pre-finalize.sh`"]
+    DCR[codeql database create<br>--command=$_build_cmd<br>--language=javascript<br>--search-path=./extractors/<br>--<br>/path/to/database]
+    DB@{ shape: cyl, label: "/path/to/database" }
+    DINIT[codeql database init]
+    CRE[codeql resolve extractor]
+    DTRAC[codeql database<br>trace-command]
+    SPF[[pre-finalize.sh]]
+    JSE[[javascript extractor]]
+    SIF[[index-files.sh]]
+    DIDX[codeql database index-files<br> --language=cds<br>--include-extension=.cds]
+    CC[[\`cds\` compiler]]
+    CDJ([.cds.json files])
+    TF([CodeQL TRAP files])
+    DBF[codeql database finalize<br> -- /path/to/database]
+
+    COM ==> DCR
+    DCR ==> |run internal CLI<br>plumbing command| DINIT
+    DINIT ----> |--language=javascript| CRE
+    CRE -..-> |/extractor/path/javascript| DINIT
+    DINIT -.initialize database.-> DB
+
+    DINIT ==> |run the<br>javascript extractor| JSE
+    SPF ==> |run the cds extractor| DIDX
+    JSE -.-> |extract javascript files:<br>_.html, .js, .json, .ts_| DB
+    DTRAC ==> |run the build --command| SPF
+    JSE ==> |run autobuild within<br>the javascript extractor| DTRAC
+    DIDX ==> |script discovered<br>via --search-path| SIF
+    SIF ==> |call the cds compiler| CC
+    CC ==> |compile .cds files to<br>create .cds.json files| CDJ
+    CDJ -.-> |extract .cds.json files<br>to database| DB
+
+    CDJ ==> |generate .trap files| TF
+    TF ==> |finalize database once<br>pre-finalize completes| DBF
+    DBF ==> |import TRAP files,<br>then cleanup| DB
+```

javascript/frameworks/cap/test/.gitignore

@@ -0,0 +1,3 @@
+# Ignore package-lock.json files for tests.
+package-lock.json
+