New "location" events' metadata field

[ferishili]

This PR fixes #114,

Description

like what is presented by Studio as the location metadata field for the new events, we now want the exact same thing to be passed as metadata field "location" and to have "Moodle" value, to determine that the uploaded video is coming from Moodle!

How it works:

• Add a new "location" event metadata field to the default metadata values that contains Moodle, and it is read-only!
• A new feature has been added to the upload forms which makes it possible for the configured metadata to have defined value as set in Parameters (JSON) column and be read-only, on the other hand the value of the read-only field in this case will be added to the form data when submitted, but not changable by the users!
  • So with this feature, if admin wants to add a pre-defined read-only metadata to have custom value, it is simply done when the metadata field in admin setting config is set to read-only and have the json format value (e.g. {"value": "Moodle"}) as for the Parameters (JSON) column

Important to know:

• As to provide an upgrade step in order to add this new metadata field, the plugin version is now set to 2024111103 for testing purposes, therefore just pay attention to this new versioning.
• It is important to also adjust the $oldversion and upgrade_block_savepoint in the upgrade.php file when this is merged and for the new release!

How to TEST

• Patch this PR
• Navigate to Admin settings of the plugin and locate Events' Metadata.
• Make sure that there is a new metadata filed called "location" which is read-only and have default value of Moodle!
• You can change "Moodle" with whatever you like.
• Make sure showlocationsetting option in Appearance section is enabled!
• Save changes
• Go to upload form/ batch upload form
• Expand the metadata fields (Show more...)
• Make sure you can locate the "Location" field which has the default value you already set in admin setting and it is read-only!
• Upload a video.
• After the video uploaded and processed, make sure you can see the value you have added as for location is presented in the table (Location column)