[Feature] Server pagination implementation (#243)

## Major Changes
- Implement a REST style API app in epapi
- Currently implements a GET method for all entity types in the browse menu (both package level and global)
- Provides paginated results per default with query style filtering for reviewed vs unreviewed.
- Provides new paginated templates with thin wrappers per entity types for easier maintainability
- Implements e2e tests for the API

## Minor changes
- Added more comprehensive gitignore to cover coverage reports and other test/node.js etc. data.
- Add additional CI file for API tests that only gets triggered on API relevant changes.

## ⚠️ Currently only works with session-based authentication. Token based will be added in new PR.

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Co-authored-by: jebus <lorsbach@envipath.com>
Reviewed-on: enviPath/enviPy#243
Co-authored-by: Tobias O <tobias.olenyi@envipath.com>
Co-committed-by: Tobias O <tobias.olenyi@envipath.com>

epapi/v1/errors.py

@@ -0,0 +1,28 @@
+from ninja.errors import HttpError
+
+
+class EPAPIError(HttpError):
+    status_code: int = 500
+
+    def __init__(self, message: str) -> None:
+        super().__init__(status_code=self.status_code, message=message)
+
+    @classmethod
+    def from_exception(cls, exc: Exception):
+        return cls(message=str(exc))
+
+
+class EPAPIUnauthorizedError(EPAPIError):
+    status_code = 401
+
+
+class EPAPIPermissionDeniedError(EPAPIError):
+    status_code = 403
+
+
+class EPAPINotFoundError(EPAPIError):
+    status_code = 404
+
+
+class EPAPIValidationError(EPAPIError):
+    status_code = 422