feat: Global Block & Keep filters

[privatmamtora]

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• [X] I have tested my changes
• [X] There is no breaking changes
• [X] I really tested my changes and there is no regression
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Added new feature to enable Global Keep & Block Rules. Advantages

• Users can keep and maintain a single set of rules that would apply to all feeds.
• Rules are strict to a specific field name specified and doesn't require the user to figure out if there are conflicts.
• Rules can be kept simple if user is having a difficulty managing their rules

Format: FieldName(RegEx)~FieldName(RegEx)~...

FieldName options: Title, URL, CommentsURL, Content, Author, Tags

Addresses: #1326 , #1654 , #1953 , #2583 (maybe)

[fguillot]

Format: FieldName(RegEx)~FieldName(RegEx)~...

FieldName options: Title, URL, CommentsURL, Content, Author, Tags

From a user perspective, I'm wondering if ~ is the right choice for rule separator. Would not be better to have one rule per line in a textarea?

The syntax could be simplified:

EntryURL=(?i)example
Title=(?i)Test

instead of

URL((?i)example)~Title((?i)Test)

I would make the field names explicit to avoid possible confusions: URL -> EntryURL.

[privatmamtora]

Ok will make the following changes:

1. Use a text area, 1 rule per-line a. Eliminates the ~ separator b. Makes it easier to modify and review rules
2. Use = to separate FieldName and rules
3. I'll change the field names to the following:
   • EntryTitle
   • EntryURL
   • EntryCommentsURL
   • EntryContent
   • EntryAuthor
   • EntryTag

[privatmamtora]

Completed making the changes @fguillot