[feature] Admin accounts endpoints; approve/reject sign-ups (#2826)

* update settings panels, add pending overview + approve/deny functions

* add admin accounts get, approve, reject

* send approved/rejected emails

* use signup URL

* docs!

* email

* swagger

* web linting

* fix email tests

* wee lil fixerinos

* use new paging logic for GetAccounts() series of admin endpoints, small changes to query building

* shuffle useAccountIDIn check *before* adding to query

* fix parse from toot react error

* use `netip.Addr`

* put valid slices in globals

* optimistic updates for account state

---------

Co-authored-by: kim <grufwub@gmail.com>

internal/email/sender.go

@@ -53,6 +53,14 @@ type Sender interface {
 	// It is expected that the toAddresses have already been filtered to ensure
 	// that they all belong to active admins + moderators.
 	SendNewSignupEmail(toAddress []string, data NewSignupData) error
+
+	// SendSignupApprovedEmail sends an email to the given address
+	// that their sign-up request has been approved by a moderator.
+	SendSignupApprovedEmail(toAddress string, data SignupApprovedData) error
+
+	// SendSignupRejectedEmail sends an email to the given address
+	// that their sign-up request has been rejected by a moderator.
+	SendSignupRejectedEmail(toAddress string, data SignupRejectedData) error
 }
 
 // NewSender returns a new email Sender interface with the given configuration, or an error if something goes wrong.