Fixed channel icon conflict when populating the database from XMLTV

[janbar]

Based on the remote filenames of the icons, conflicts can arise, causing a mess:

<icon src="https://static.te.../stations/308/icon320_light.png?v2023_48_0"/>
<icon src="https://static.te.../stations/58/icon320_light.png?v2023_48_0"/>
<icon src="https://static.te.../stations/383/icon320_light.png?v2023_48_0"/>

These cases generates the same icon filename 'icon320_light.png?v2023_48_0'.

The proposed solution no longer uses the original filename; it now generates a user-friendly name from the source identifier of channel (xmltvid), followed by the hash of the full remote URL and, optionally, the file extension. This way, the generated name can no longer conflict with that of another channel, and it is easily identifiable with the xmltv identifier, as it is user-configured.

<xmltv_id>_<remote_url_hash>.<ext>

Now downloaded icon names from xmltv source look like the following.

T18.fr_2fcaf706.svg.png
NOVO19.fr_d890da17.svg.png
TMC.fr_79bd517.png

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[garybuhrmaster]

While I understand your particular issues,this feels like an incomplete (and therefore wrong) solution.

In my case, for one guide source, the base names are entirely meaningful and useful (includes the channel and network association), and hiding them inside some opaque hash would be a disservice (perhaps unless you want to go whole hog and create a unique uuid based channel icon blob table which has automatic deletion when there are no longer any references, but that is probably a bridge too far).

And the xmltv is only unique within a sourceid (when you have multiple guide sources), as the same xmltv (which is defined only by the source) can be reused by other sourceids (yes, there is the RFC2838 standard,but not all guide sources use it).

Instead, I would suggest that as the xmltv will be only unique within the sourceid, that the (default) names should be something of the form of sourceid_xmltv_base_url_name.

[janbar]

@garybuhrmaster , I amended the initial commit. Thanks for review.