Refactor custom filters

[smalluban]

Moves the generation logic and fixes some minor bugs of the custom filters feature.

• Adds options.customFilters.enabled property and on/off feature of the custom filters without the need to remove the whole textarea content to temporarily disable custom filters
• Fixes minor issues, where for example DNR rules were not set at all if only one rule did not convert - which was not consistent with the behavior for network filters in the engine (Firefox)
• Simplifies the components/custom-filters.js file - as this should be a component, not a file with that much logic, which is not related to the UI
• The only "drawback" is removed instant feedback with counters of filters below the textarea. This code moved to the BG. However, I think it was misleading, as the DNR rule might fail when it's converted, not when you pass them there. The feedback stays, but after you make an update to the custom filters.

I tried to not change the logic, but in some places, it looked to me like obvious bugs - please review this code not as an update, but as a whole - if this works as you would expected it to work.

[smalluban]

@philipp-classen Updated and fixed what I could change. The parseInput must stay, but I renamed it to normalizeFilters, as it better describes what actually the function does - it does not produce filters, just split the input into buckets, and fixes scriptlets if needed.

[github-actions]

Builds for commit df3ef39:

• ghostery-chrome-10.4.1-df3ef39
• ghostery-edge-10.4.1-df3ef39
• ghostery-firefox-10.4.1-df3ef39
• ghostery-opera-10.4.1-df3ef39

[smalluban]

@GRadziejewski Testing highlights:

• The feature logic has not changed
• Added on/off toggle for the whole feature, so we can disable custom filters without removing the input
• Fixed issue with updated adblocker engine - to proof the bug update 3.18 -> 4.0, to proof the fix 3.18 -> 4.0 -> this PR - The bug cleans out the engine, so the cosmetic filters and network filters (only Firefox) are removed. The best way to test - add custom filters before updating to 4.0, then check out that custom filters don't work anymore until the next update.

[GRadziejewski]

Test results: #1822 (comment)

Issue: #1823

[smalluban]

After testing the feature, I added a small change to not confuse users - the "Update" (actually "Save" now - it's more what it is, and it's already translated phrase) is disabled only when filters update.
Also, it fixes the state when the global pause is turned on.

[github-actions]

Builds for commit abea2cb:

• ghostery-chrome-10.4.1-abea2cb
• ghostery-edge-10.4.1-abea2cb
• ghostery-firefox-10.4.1-abea2cb
• ghostery-opera-10.4.1-abea2cb

[GRadziejewski]

Test results: #1822

LGTM.