The Qt lupdate tool that extracts translatable strings from .qml files
writes paths relative to its output .ts file into the .ts file.
These paths are then retained as-is when converted to .pot format.
The last few commits moved around the working directory of the lupdate tool
(from electrum/locale to electrum/locale/build), which resulted in a change
of all relative paths in the final messages.pot we upload to crowdin.
E.g. from:
```
#: ../gui/qml/components/Addresses.qml:64
```
to:
```
#: ../../gui/qml/components/Addresses.qml:64
```
I think a change like this does not invalidate the translations. Still, it is annoying.
This commit adds an extra processing step to "fix" these strings to:
```
#: electrum/gui/qml/components/Addresses.qml:64
```