init.el: Remove gtags support

We can use etags with emacs which works nicely with
xref and auto complete. gtags which we were primarily
using for C is not required.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>

init.el

@@ -177,19 +177,6 @@
              (setq helm-projectile-fuzzy-match t)
              :config
              (helm-projectile-on))
-;; Helm Gtags
-(use-package helm-gtags
-             :defer t
-             :ensure t
-             :init
-             (progn
-               (setq helm-gtags-ignore-case t
-                     helm-gtags-auto-update t
-                     helm-gtags-prefix-key "SPC"
-                     helm-gtags-use-input-at-cursor t
-                     helm-gtags-pulse-at-cursor t)
-               ;; enable gtags only for C
-               (add-hook 'c-mode-hook 'helm-gtags-mode)))
 
 ;; All The Icons
 (use-package all-the-icons :ensure t)
@@ -291,33 +278,6 @@
                "qr"  '(restart-emacs :which-key "restart emacs")
                ;; Others
                "at"  '(eshell :which-key "open terminal")
-               ;; Gtags
-               "mgc" '(helm-gtags-create-tags
-                        :which-key "create tag db")
-               "mgd" '(helm-gtags-find-tag
-                        :which-key "find definitions")
-               "mgf" '(helm-gtags-select-path
-                        :which-key "jump to a file in tag db")
-               "mgG" '(helm-gtags-dwim-other-window
-                        :which-key "jump to location based on context")
-               "mgi" '(helm-gtags-tags-in-this-function
-                        :which-key "present tags in current function")
-               "mgl" '(helm-gtags-parse-file
-                        :which-key "jump to definitions in file")
-               "mgn" '(helm-gtags-next-history
-                        :which-key "jump to next location in context stack")
-               "mgp" '(helm-gtags-previous-history
-                        :which-key "jump to previous location in context stack")
-               "mgr" '(helm-gtags-find-rtag
-                        :which-key "find references")
-               "mgR" '(helm-gtags-resume
-                        :which-key "resume previous helm-gtags session")
-               "mgs" '(helm-gtags-select
-                        :which-key "select any tag in project retrieved by gtags")
-               "mgS" '(helm-gtags-show-stack
-                        :which-key "show stack of visited locations")
-               "mgu" '(helm-gtags-update-tags
-                        :which-key "create tag db")
                ;; Magit key bindings
                "gc"  '(magit-clone
                         :which-key "magit clone")
@@ -681,14 +641,6 @@
         (call-interactively 'git-link-commit))
     (call-interactively 'git-link-commit)))
 
-(defun helm-gtags-dwim-other-window ()
-  ;; Enable helm-gtags-dwim in the other window
-  (interactive)
-  (let ((helm-gtags--use-otherwin t)
-        (split-height-threshold nil)
-        (split-width-threshold 140))
-    (helm-gtags-dwim)))
-
 (defun go-run-main ()
   (interactive)
   (shell-command