Deprecate Pallet `decl_*` Macros (#13705)

* Deprecate decl_ macros

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Allow deprecated in tests

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Revert "Allow deprecated in tests"

This reverts commit ce36080f9bb4079e9069af8ee02e0954753ae412.

* Deprecate all

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Push missing files

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* fmt

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Move decl_module to own file

Otherwise i have to spam allow(deprecated) for all recursive calls.

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Revert "Move decl_module to own file"

This reverts commit 543a31185cda708d417127d6cb89cdc0c31d1f34.

* Fix tests

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

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Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>