fix: maven use groupId:artifactId for package name concatenation (#6352)

Second part of #6327 to fix the Maven package naming. This pull request includes:
* Changing the group and artifact IDs from being separated by `-` to `:` as suggested by [Maven](https://maven.apache.org/pom.html#Maven_Coordinates).
* Making Maven package names case-sensitive
* Migrating the database to:
  * Handle collisions of package names (e.g., groupId: foo- with artifactId: bar and groupId: foo with artifactId: -bar) by moving them into their own packages.
  * Fix the missing group ID issue (#6329).
  * Update  lower_name to match the name value for maven pkgs to make it case-sensetive.

## Checklist

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### Tests

- I added test coverage for Go changes...
  - [x] in their respective `*_test.go` for unit tests.
  - [x] in the `tests/integration` directory if it involves interactions with a live Forgejo server.
- I added test coverage for JavaScript changes...
  - [ ] in `web_src/js/*.test.js` if it can be unit tested.
  - [ ] in `tests/e2e/*.test.e2e.js` if it requires interactions with a live Forgejo server (see also the [developer guide for JavaScript testing](https://codeberg.org/forgejo/forgejo/src/branch/forgejo/tests/e2e/README.md#end-to-end-tests)).

### Documentation

- [ ] I created a pull request [to the documentation](https://codeberg.org/forgejo/docs) to explain to Forgejo users how to use this change.
- [x] I did not document these changes and I do not expect someone else to do it.

### Release notes

- [ ] I do not want this change to show in the release notes.
- [x] I want the title to show in the release notes with a link to this pull request.
- [ ] I want the content of the `release-notes/<pull request number>.md` to be be used for the release notes instead of the title.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/6352
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: Julian Schlarb <julian.schlarb@denktmit.de>
Co-committed-by: Julian Schlarb <julian.schlarb@denktmit.de>

tests/integration/api_packages_maven_test.go

@@ -29,12 +29,12 @@ func TestPackageMaven(t *testing.T) {
 
 	groupID := "com.gitea"
 	artifactID := "test-project"
-	packageName := groupID + "-" + artifactID
+	packageName := groupID + ":" + artifactID
 	packageVersion := "1.0.1"
 	packageDescription := "Test Description"
 
 	root := fmt.Sprintf("/api/packages/%s/maven/%s/%s", user.Name, strings.ReplaceAll(groupID, ".", "/"), artifactID)
-	filename := fmt.Sprintf("%s-%s.jar", packageName, packageVersion)
+	filename := fmt.Sprintf("%s:%s.jar", packageName, packageVersion)
 
 	putFile := func(t *testing.T, path, content string, expectedStatus int) {
 		req := NewRequestWithBody(t, "PUT", root+path, strings.NewReader(content)).
@@ -249,7 +249,7 @@ func TestPackageMaven(t *testing.T) {
 
 		partialVersion := packageVersion + "-PARTIAL"
 		putFile(t, fmt.Sprintf("/%s/%s", partialVersion, filename), "test", http.StatusCreated)
-		pkgUIURL := fmt.Sprintf("/%s/-/packages/maven/%s-%s/%s", user.Name, groupID, artifactID, partialVersion)
+		pkgUIURL := fmt.Sprintf("/%s/-/packages/maven/%s:%s/%s", user.Name, groupID, artifactID, partialVersion)
 		req := NewRequest(t, "GET", pkgUIURL)
 		resp := MakeRequest(t, req, http.StatusOK)
 		assert.NotContains(t, resp.Body.String(), "Internal server error")