Add package.json for MIP package manager

Also add a tool for generating package.json, so it doesn't have
to be handcrafted when files are added/removed.

To generate/update package.json, run from repo root as follows:

python3 tools/genpkgjson.py > package.json

(instead of python3, micropython can also be used)

Note: at present MIP does not support any way to specify repo-relative
urls, so at present the generated json will point to
gituhub:micropython/micropython-esp32-ulp, which would need to be
adapted in any forks of this repo.

package.json

@@ -0,0 +1,19 @@
+{
+  "v":1,
+  "urls":[
+    ["esp32_ulp/__init__.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/__init__.py"],
+    ["esp32_ulp/__main__.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/__main__.py"],
+    ["esp32_ulp/assemble.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/assemble.py"],
+    ["esp32_ulp/definesdb.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/definesdb.py"],
+    ["esp32_ulp/link.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/link.py"],
+    ["esp32_ulp/nocomment.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/nocomment.py"],
+    ["esp32_ulp/opcodes.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/opcodes.py"],
+    ["esp32_ulp/opcodes_s2.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/opcodes_s2.py"],
+    ["esp32_ulp/parse_to_db.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/parse_to_db.py"],
+    ["esp32_ulp/preprocess.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/preprocess.py"],
+    ["esp32_ulp/soc.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/soc.py"],
+    ["esp32_ulp/soc_s2.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/soc_s2.py"],
+    ["esp32_ulp/soc_s3.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/soc_s3.py"],
+    ["esp32_ulp/util.py", "github:micropython/micropython-esp32-ulp/esp32_ulp/util.py"]
+  ]
+}

tools/genpkgjson.py

@@ -0,0 +1,50 @@
+"""
+Tool for generating package.json for the MIP package manager
+
+Run this tool from the repo root, like:
+
+python tools/genpkgjson.py > package.json
+
+Note:
+This tool works with both python3 and micropyton.
+"""
+
+import os
+import json
+
+PACKAGE_JSON_VERSION=1
+
+# Update the repo when working with a fork
+GITHUB_REPO="micropython/micropython-esp32-ulp"
+
+
+def get_files(path):
+    files = [f'{path}/{f}' for f in os.listdir(path)]
+    return files
+
+
+def build_urls(repo_base, files):
+    return [[f, f'github:{repo_base}/{f}'] for f in files]
+
+
+def print_package_json(urls):
+    """
+    Custom-formatting JSON output for better readability
+
+    json.dumps in MicroPython cannot format the output and python3
+    puts each element of each urls' sub-arrays onto a new line.
+    Here we print each file and its source url onto the same line.
+    """
+    print('{')
+    print(f'  "v":{PACKAGE_JSON_VERSION},')
+    print('  "urls":[')
+    print(',\n'.join([f'    {json.dumps(u)}' for u in sorted(urls)]))
+    print('  ]')
+    print('}')
+
+
+if __name__ == '__main__':
+    library_root = 'esp32_ulp'
+    files = get_files(library_root)
+    urls = build_urls(GITHUB_REPO, files)
+    print_package_json(urls)