fix(fyler-nvim): Refactor options for file explorer configuration

[burgr033]

📑 Description

upstream fyler changed their options. It gave a warning message about deprecating the options used in the astrocommunity fork. this pr changes the options to match the structure of fyler.nvim

📖 Additional Information

message

Fyler: Deprecated configuration options detected
============================================================

Deprecated configuration detected: 'default_explorer'
  Configuration structure reorganized under 'views.finder'
  Use 'views.finder.default_explorer' instead
  Update your config: views.finder.default_explorer = true

Deprecated configuration detected: 'indentscope'
  Configuration structure reorganized under 'views.finder'
  Use 'views.finder.indentscope' instead
  Update your config: views.finder.indentscope = {
  marker = "┊"
}

Deprecated configuration detected: 'win'
  Configuration structure reorganized under 'views.finder'
  Use 'views.finder.win' instead
  Update your config: views.finder.win = {
  border = "rounded",
  kind = "replace"
}

============================================================
Please update your configuration to avoid future issues.
See :h Fyler.Config for current options.