Fix: AttributeError: 'dict' object has no attribute 'parenttype'

[fix] Data Import Template with Data: Sort by  when nested set model

```python
Traceback (innermost last):
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/app.py", line 57, in application
    response = frappe.handler.handle()
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/handler.py", line 19, in handle
    execute_cmd(cmd)
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/handler.py", line 36, in execute_cmd
    ret = frappe.call(method, **frappe.form_dict)
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/__init__.py", line 805, in call
    return fn(*args, **newargs)
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/client.py", line 79, in insert
    parent.append(doc)
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/model/base_document.py", line 130, in append
    if not self.__dict__.get(key):
 TypeError: unhashable type: 'dict'
```

```python
Traceback (innermost last):
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/app.py", line 57, in application
    response = frappe.handler.handle()
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/handler.py", line 19, in handle
    execute_cmd(cmd)
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/handler.py", line 36, in execute_cmd
    ret = frappe.call(method, **frappe.form_dict)
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/__init__.py", line 805, in call
    return fn(*args, **newargs)
  File "/usr/frappe5/frappe-bench/apps/frappe/frappe/client.py", line 78, in insert
    parent = frappe.get_doc(doc.parenttype, doc.parent)
 AttributeError: 'dict' object has no attribute 'parenttype'
```

[minor] [fix] mimetype in render.py

[fix] Exception handling while uploading backups to dropbox

Unset `toolbar.current_status` on `disable_save`

[Enhancement] Online and Offline POS

If the `cur_frm.toolbar.current_status` is not unset, when, `cur_frm.toolbar.enable_save` is called the `Save` button on form is not reloaded!

To certify just go to a form, open the browser console and run

```
cur_frm.disable_save();
cur_frm.enable_save();
```

Without this fix, the button will not released!

[cleanup] simpler logging system that does not affect other loggers

Blog UI changes and Clean up

Added validation for App Title

Added data-link to issues tab under navbar

Build columns only if field exists