[2.0.0-alpha3] Rename source plugins

Rename FieldPropertySourceProp

All our source plugins follow a consistent naming pattern, expect one

ui_patterns:

• UrlWidget.php: * id = "url",
• FieldPropertySourceProp.php: * id = "field_properties_source_prop" ⚠️
• BreadcrumbSource.php: * id = "breadcrumb",
• PathSource.php: * id = "path",
• TokenSource.php: * id = "token",
• NumberWidget.php: * id = "number",
• CheckboxesWidget.php: * id = "checkboxes",
• ListTextareaWidget.php: * id = "list_textarea",
• MenuSource.php: * id = "menu",
• SelectWidget.php: * id = "select",
• BlockSource.php: * id = "block",
• CheckboxWidget.php: * id = "checkbox",
• TextfieldWidget.php: * id = "textfield",
• WysiwygWidget.php: * id = "wysiwyg",
• AttributesWidget.php: * id = "attributes",

ui_patterns_field_formatters

• FieldFormatterSource.php: * id = "field_formater",
• FieldLabelSource.php: * id = "field_label",

ui_patterns_views

• ViewFieldSource.php: * id = "view_field",
• ViewGroupTitleSource.php: * id = "view_group_title",
• ViewRowsSource.php: * id = "view_rows",

So, is it relevant to rename:

• FieldPropertySourceProp.php >> FieldPropertySource.php ?
• field_properties_source_prop >> field_property ?
• FieldPropertiesSourcePropDeriver >> FieldPropertySourceDeriver ?

Rename FieldPropertySourceBase

Now, lets have a look on class hierarchy of FieldPropertySourceBase:

SourcePluginBase
  ui_patterns / FieldSourceBase
    ui_patterns_field_formatters / FieldLabelSource
    ui_patterns / FieldPropertySourceBase ⚠️
      ui_patterns / FieldPropertySourceProp
      ui_patterns_field_formatters / FieldFormatterSource

It is weird to have "FieldPropertySourceBase" as a parent of "FieldFormatterSource". Can we rename it? How?

Rename EntityLinksUrlSource

• EntityLinksUrlSource.php >> EntityLinkSource.php.php
• "Entity Link URL" >> "Entity link" (plugin names are always sentence case)
• entity_link_url >> entity_link