patch 8.1.2070: mouse code is spread out

Problem:    Mouse code is spread out.
Solution:   Move mouse terminal code parsing to mouse.c. (Yegappan Lakshmanan,
            closes #4966)
diff --git a/src/proto/term.pro b/src/proto/term.pro
index 50e2f5e..a7a051c 100644
--- a/src/proto/term.pro
+++ b/src/proto/term.pro
@@ -32,6 +32,7 @@
 void term_pop_title(int which);
 void ttest(int pairs);
 void add_long_to_buf(long_u val, char_u *dst);
+int get_bytes_from_buf(char_u *buf, char_u *bytes, int num_bytes);
 void check_shellsize(void);
 void limit_screen_size(void);
 void win_new_shellsize(void);
@@ -59,8 +60,10 @@
 void add_termcode(char_u *name, char_u *string, int flags);
 char_u *find_termcode(char_u *name);
 char_u *get_termcode(int i);
+int get_termcode_len(int idx);
 void del_termcode(char_u *name);
 void set_mouse_topline(win_T *wp);
+int is_mouse_topline(win_T *wp);
 int check_termcode(int max_offset, char_u *buf, int bufsize, int *buflen);
 void term_get_fg_color(char_u *r, char_u *g, char_u *b);
 void term_get_bg_color(char_u *r, char_u *g, char_u *b);