partitioning - Ubuntu 18.04 boot too small - can't resize

I am unable to upgrade software since upgrading to 18.04 due to the boot partition size being too small. I've tried Gparted as a LiveCD, but that didn't allow me to expand the boot partition. I can't get KVPM to boot due to needing to be root and I can't find instructions on how to make that happen.

I also can't install system-config-lvm for some reason. I've used several sources, but this link has most of the instructions I've followed thus far:

How can I resize an LVM partition? (i.e: physical volume)

Outside of doing a clean install to fix the boot partition size problem, I'm hoping someone can help me resize the partitions on my machine so I can get past this roadblock.

Thanks in advance.

Output of df -h

Output of df -i

Software updater error message:

Software Updater "Not enough free disk space" error

Output of ls -la /boot:

total 110844
drwxr-xr-x  4 root root     4096 Nov 17 11:50 .
drwxr-xr-x 24 root root     4096 Nov 15 19:26 ..
-rw-r--r--  1 root root  1537821 Sep 24 07:08 abi-4.15.0-36-generic
-rw-r--r--  1 root root  1537997 Oct 10 02:20 abi-4.15.0-38-generic
-rw-r--r--  1 root root   216954 Sep 24 07:08 config-4.15.0-36-generic
-rw-r--r--  1 root root   216983 Oct 10 02:20 config-4.15.0-38-generic
drwxr-xr-x  5 root root     1024 Nov 15 19:27 grub
-rw-r--r--  1 root root 26584853 Nov 15 19:26 initrd.img-4.15.0-36-generic
-rw-r--r--  1 root root 57729589 Nov 17 11:50 initrd.img-4.15.0-38-generic
drwx------  2 root root    12288 Nov 15  2014 lost+found
-rw-r--r--  1 root root   182704 Jan 28  2016 memtest86+.bin
-rw-r--r--  1 root root   184380 Jan 28  2016 memtest86+.elf
-rw-r--r--  1 root root   184840 Jan 28  2016 memtest86+_multiboot.bin
-rw-r--r--  1 root root        0 Sep 24 07:08 retpoline-4.15.0-36-generic
-rw-r--r--  1 root root        0 Oct 10 02:20 retpoline-4.15.0-38-generic
-rw-------  1 root root  4046393 Sep 24 07:08 System.map-4.15.0-36-generic
-rw-------  1 root root  4046910 Oct 10 02:20 System.map-4.15.0-38-generic
-rw-------  1 root root  8275824 Sep 24 07:08 vmlinuz-4.15.0-36-generic
-rw-------  1 root root  8277752 Oct 10 03:43 vmlinuz-4.15.0-38-generic

New df-h output after removing old kernel:

Filesystem                   Size  Used Avail Use% Mounted on
udev                         5.9G     0  5.9G   0% /dev
tmpfs                        1.2G  2.1M  1.2G   1% /run
/dev/mapper/ubuntu--vg-root  905G  347G  513G  41% /
tmpfs                        5.9G  3.0M  5.9G   1% /dev/shm
tmpfs                        5.0M  4.0K  5.0M   1% /run/lock
tmpfs                        5.9G     0  5.9G   0% /sys/fs/cgroup
/dev/loop0                    88M   88M     0 100% /snap/core/5742
/dev/loop1                    89M   89M     0 100% /snap/core/5897
/dev/loop2                   203M  203M     0 100% /snap/firefox/152
/dev/loop3                   5.0M  5.0M     0 100% /snap/canonical-livepatch/50
/dev/loop4                    88M   88M     0 100% /snap/core/5662
/dev/sda1                    236M  117M  107M  53% /boot
tmpfs                        1.2G   16K  1.2G   1% /run/user/127
tmpfs                        1.2G   32K  1.2G   1% /run/user/1000

:/boot$ ls -la
total 110844
drwxr-xr-x  4 root root     4096 Nov 17 11:50 .
drwxr-xr-x 24 root root     4096 Nov 15 19:26 ..
-rw-r--r--  1 root root  1537821 Sep 24 07:08 abi-4.15.0-36-generic
-rw-r--r--  1 root root  1537997 Oct 10 02:20 abi-4.15.0-38-generic
-rw-r--r--  1 root root   216954 Sep 24 07:08 config-4.15.0-36-generic
-rw-r--r--  1 root root   216983 Oct 10 02:20 config-4.15.0-38-generic
drwxr-xr-x  5 root root     1024 Nov 15 19:27 grub
-rw-r--r--  1 root root 26584853 Nov 15 19:26 initrd.img-4.15.0-36-generic
-rw-r--r--  1 root root 57729589 Nov 17 11:50 initrd.img-4.15.0-38-generic
drwx------  2 root root    12288 Nov 15  2014 lost+found
-rw-r--r--  1 root root   182704 Jan 28  2016 memtest86+.bin
-rw-r--r--  1 root root   184380 Jan 28  2016 memtest86+.elf
-rw-r--r--  1 root root   184840 Jan 28  2016 memtest86+_multiboot.bin
-rw-r--r--  1 root root        0 Sep 24 07:08 retpoline-4.15.0-36-generic
-rw-r--r--  1 root root        0 Oct 10 02:20 retpoline-4.15.0-38-generic
-rw-------  1 root root  4046393 Sep 24 07:08 System.map-4.15.0-36-generic
-rw-------  1 root root  4046910 Oct 10 02:20 System.map-4.15.0-38-generic
-rw-------  1 root root  8275824 Sep 24 07:08 vmlinuz-4.15.0-36-generic
-rw-------  1 root root  8277752 Oct 10 03:43 vmlinuz-4.15.0-38-generic

:/boot$ sudo apt remove linux-image-4.15.0-36-generic
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package 'linux-image-4.15.0-36-generic' is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 76 not upgraded.