Replace banklinks with linkpay

[DinSmol]

close #2210
Replaced banklinks with linkpay (everypay).
Added linkpay to email and pdf.
Added qr to pdf.

I tested this PR on staging, but it does not work with linkpay callback, because of the VPN.
Because of it, I imitated a response from the EveryPay inside our VPN and the app worked correctly.

[viezly]

This pull request is split into 6 parts for easier review.
👀 Review pull request on Viezly

Changed files are located in these folders:

• /
• app/controllers/registrar
• app/mailers
• app/models
• app/views
• config
• test
• test/system/registrar_area/invoices

[vohmar]

merge conflicts and deploy error due to component versions:

fatal: [staging.internet.ee]: FAILED! => {
"changed": false,
"cmd": "/home/registry/.rbenv/shims/bundle install",
"invocation": {
"module_args": {
"binstub_directory": null,
"chdir": "/home/registry/deploy/releases/20220406135955",
"clean": false,
"deployment_mode": false,
"exclude_groups": null,
"executable": null,
"extra_args": null,
"gem_path": null,
"gemfile": null,
"local": false,
"state": "present",
"user_install": true
}
},
"msg": "Calling DidYouMean::SPELL_CHECKERS.merge!(error_name => spell_checker)' has been deprecated. Please call DidYouMean.correct_error(error_name, spell_checker)' instead.\nnokogiri-1.12.5-x86_64-linux requires ruby version < 3.1.dev, >= 2.5, which is\nincompatible with the current version, ruby 3.1.0p0",
"rc": 5,
"stderr": "Calling DidYouMean::SPELL_CHECKERS.merge!(error_name => spell_checker)' has been deprecated. Please call DidYouMean.correct_error(error_name, spell_checker)' instead.\nnokogiri-1.12.5-x86_64-linux requires ruby version < 3.1.dev, >= 2.5, which is\nincompatible with the current version, ruby 3.1.0p0\n",
"stderr_lines": [
"Calling DidYouMean::SPELL_CHECKERS.merge!(error_name => spell_checker)' has been deprecated. Please call DidYouMean.correct_error(error_name, spell_checker)' instead.",
"nokogiri-1.12.5-x86_64-linux requires ruby version < 3.1.dev, >= 2.5, which is",
"incompatible with the current version, ruby 3.1.0p0"
],
"stdout": "Fetching gem metadata from https://rubygems.org/..........\n",
"stdout_lines": [
"Fetching gem metadata from https://rubygems.org/.........."

[vohmar]

already done in another branch