Add photo feature

[Discostu36]

Add photography feature. This is only the basic implementation without upload functionality.

• Create button in the object modal (Add object modal #6) that triggers photo intent with choice between choosing from gallery and launching photo app
• Decide where photos should be stored and if this should be handled differently when photo came from gallery or from photo app (see below)
• Decide file naming scheme. (See below)

[Discostu36]

Internal file naming (before upload):

Internally, a combination of OSM object ID and timestamp should be used:

{OSM-type}-{OSM-ID}-{Date}-{Time}.jpg

For example:
w-220007671-20220815-123523.jpg

For the unusual case of more than one photo in the same second, a dash followed by number is added.

w-220007671-20220815-123523-1.jpg

Files that were not taken with the app but imported, get -import added at the end, because they will be handled differently after upload.

w-220007671-20220815-123523-import.jpg

[Discostu36]

Standard file handling:

Photos taken with the app or imported from gallery are stored in a subfolder of the app. After upload to Wikimedia Commons, photos taken with the app are renamed and moved to 0/DCIM/OSM_Photos. The copies of imported photos are deleted.

Later, there should be a possibility to configure that behaviour. (#13)